Endosomes shuttle select cargoes between cellular compartments and, in doing so, maintain intracellular homeostasis and enable interactions with the extracellular space. Directionality of endosomal transport critically impinges on cargo fate, as retrograde (microtubule minus‐end directed) traffic delivers vesicle contents to the lysosome for proteolysis, while the opposing anterograde (plus‐end directed) movement promotes recycling and secretion. Intriguingly, the endoplasmic reticulum (ER) is emerging as a key player in spatiotemporal control of late endosome and lysosome transport, through the establishment (...) of physical contacts with these organelles. Earlier studies have described how minus‐end‐directed motor proteins become discharged from vesicles engaged at such contact sites. Now, Raiborg et al. implicate ER‐mediated interactions, induced by protrudin, in loading plus‐end‐directed motor kinesin‐1 onto endosomes, thereby stimulating their transport toward the cell's periphery. In this review, we recast the prevailing concepts on bidirectional late endosome transport and discuss the emerging paradigm of inter‐compartmental regulation from the ER‐endosome interface viewpoint. (shrink)

Intercellular communication is an essential process in all multicellular organisms. During this process, molecules secreted by one cell will bind to a receptor on the cognate cell leading to the subsequent uptake of the receptor‐ligand complex. Once inside, the cell then determines the fate of the receptor‐ligand complex and any other proteins that were endocytosed together. Approximately 80% of endocytosed material is recycled back to the plasma membrane either directly or indirectly via the Golgi apparatus and the remaining 20% is (...) delivered to the lysosome for degradation. Although most pathways have been identified, we still lack understanding on how specificity in sorting of recycling cargos into different pathways is achieved, and how the cell reaches high accuracy of these processes in the absence of clear sorting signals in the bulk of the client proteins. In this review, we will summarize our current understanding of the mechanism behind recycling cargo sorting and propose a model of differential affinities between cargo and cargo receptors/adaptors with regards to iterative sorting in endosomes. (shrink)

The rate‐limiting step in the uptake and metabolism of Dglucose by insulin target cells is thought to be glucose transport mediated by glucose transporters (primarily the GLUT4 isoform) localized to the plasma membrane. However, subcellular fractionation, photolabelling and immunocytochemical studies have shown that the pool of GLUT4 present in the plasma membrane is only one of many subcellular pools of this protein. GLUT4 has been found in occluded vesicles at the plasma membrane, clathrin‐coated pits and vesicles, early endosomes, and (...) tubulo‐vesicular structures; the latter are analogous to known specialized secretory compartments. Tracking the movement of GLUT4 through these compartments, and defining the mechanism and site of action of insulin in stimulating this subcellular trafficking, are major topics of current investigation. Recent evidence focuses attention on the exocytosis of GLUT4 as the major site of insulin action. Increased exocytosis may be due to decreased retention of glucose transporters in an intracellular pool, or possibly to increased assembly of a vesicle docking and fusion complex. Although details are unknown, the presence in GLUT4 vesicles of a synaptobrevin homologue leads us to propose that a process analogous to that occurring in synaptic vesicle trafficking is involved in the assembly of GLUT4 vesicles into a form suitable for fusion with the plasma membrane. Evidence that the pathways of signalling from the insulin receptor and of GLUT4 vesicle exocytosis may converge at the level of the key signalling enzyme, phosphatidylinositol 3‐kinase, is discussed. (shrink)

Neurons have developed elaborate mechanisms for sorting of proteins to their destination in dendrites and axons as well as dynamic local trafficking. Recent evidence suggests that polarized axonal sorting of β‐site converting enzyme 1 (BACE1), a type I transmembrane aspartyl protease involved in Alzheimer's disease (AD) pathogenesis, entails an unusual journey. In hippocampal neurons, BACE1 internalized from dendrites is conveyed in recycling endosomes via unidirectional retrograde transport towards the soma and sorted to axons where BACE1 becomes enriched. In comparison (...) to other transmembrane proteins that undergo transcytosis or elimination in somatodendritic compartment, vectorial transport of internalized BACE1 in dendrites is unique and intriguing. Dysfunction of protein transport contributes to pathogenesis of AD and other neurodegenerative diseases. Therefore, characterization of BACE1 transcytosis is an important addition to the multiple lines of evidence that highlight the crucial role played by endosomal trafficking pathway as well as axonal sorting mechanisms in AD pathogenesis. (shrink)

The Endosomal Sorting Complexes Required for Transport (ESCRTs) drive membrane remodeling in a variety of cellular processes that include the formation of endosomal intralumenal vesicles (ILVs) during multivesicular body (MVB) biogenesis. During MVB sorting, ESCRTs recognize ubiquitin (Ub) attached to membrane protein cargo and execute ILV formation by controlling the activities of ESCRT‐III polymers regulated by the AAA‐ATPase Vps4. Exactly how these events are coordinated to ensure proper cargo loading into ILVs remains unclear. Here we discuss recent work documenting (...) the ability of Bro1, an ESCRT‐associated Ub‐binding protein, to coordinate ESCRT‐III and Vps4‐dependent ILV biogenesis with upstream events such as cargo recognition. (shrink)

Microautophagy is originally defined as lysosomal (vacuolar) membrane dynamics to directly enwrap and transport cytosolic components into the lumen of the lytic organelle. Molecular details of microautophagy had remained unknown until genetic studies in yeast identified a set of proteins required for the process. Subsequent studies with other experimental model organisms resulted in a series of discoveries that accompanied an expansion of the definition of microautophagy to also encompass endosomal membrane dynamics. These findings, however, still impose puzzling, non‐integrated images (...) as to the molecular mechanism of microautophagy. By reviewing recent studies on microautophagy in various experimental systems, we propose the classification of microautophagy into three types, as the basis for developing a comprehensive view of the process. (shrink)

Recently it has become clear that trafficking of integrins to late endosomes is key to the regulation of integrin expression and function during cell migration. Here we discuss the molecular machinery that dictates whether integrins are sorted to recycling endosomes or are targeted to late endosomes and lysosomes. Integrins and other receptors that are sorted to late endosomes are not necessarily degraded and, under certain circumstances, can be spared destruction and returned to the cell surface to drive cell migration and (...) invasion. We will discuss how the exchange of adhesion receptors and other key regulators of cell migration between late endosomes/lysosomes and the plasma membrane can promote dynamic turnover of adhesions during cell migration. (shrink)

Actors, undercover investigators, and readers of fiction sometimes report “losing themselves” in the characters they imitate or read about. They speak of “taking on” or “assuming” the beliefs, thoughts, and feelings of someone else. I offer an account of this strange but familiar phenomenon—what I call imaginative transportation.

In Southeast Asian countries (SEA), road transport accounts for the main energy consumption and CO2 emission. Air pollution is a major concern in densely populated cities such as Bangkok, Manila, and Kuala Lumpur. The main objective of this paper is to give insights on trends of transport development, car ownership, and CO2 emissions in Southeast Asia. This study also attempts to review the successful transportation policies around the globe and to introduce the possible instruments that can help reduce (...) air pollution in Southeast Asian countries. Economic instruments to estimate the benefits of a cleaner environment due to new policies are introduced as well. The results of this research could help policy makers consider approaches that could internalize external costs of transportation and maximize the societal welfare. (shrink)

Endosomes, which comprise a diverse population of membrane vesicles and tubules, sort proteins and lipids to various cellular destinations. The organization and functions of these pleiomorphic cellular organelles have been extensively studied. Matsuo et al.1 now provide new exciting evidence on the role of lysobiphosphatidic acid (LBPA), a resident phospholipid of internal vesicles of the late endosome, in the control of membrane invagination and endosome biogenesis. In vivo, LBPA functions are controlled by the adaptor protein Alix and depend (...) on pH gradients along the endosomal compartments. BioEssays 26:604–607, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

This chapter contains sections titled: The Transportation System Transportation System Benefits, Harms and Hazards Conclusions and Further Questions References and Further Reading.

The transport of molecules across the nuclear envelope plays a central role in the metabolism of the cell. Significant advances hi three major areas highlight the limits of our current knowledge and point to the prospect of exciting future developments. Firstly, findings that ions and small proteins do not diffuse freely into the nucleus call into question the current views of nuclear envelope permeability. Secondly, indications that nuclear protein import can be regulated in conjunction with the cell cycle and (...) development have been confirmed by the clear demonstration of regulated nuclear entry of specific transcription factors and morphogens. Thirdly, identification and characterisation of candidate receptor proteins indicates that the recognition of the nuclear targeting sequence occurs in the cytoplasm, suggesting that a different recognition event occurs at the nuclear pore. (shrink)

The Gram-negative outer membrane is a potent permeability barrier against antibiotics, limiting clinical options amid mounting rates of resistance. The Lol transport pathway delivers lipoproteins to the OM. All the OM assembly machines require one or more OM lipoprotein to function, making the Lol pathway central for all aspects of OM biogenesis. The Lol pathways of many medically important species clearly deviate from the Escherichia coli paradigm, perhaps with implications for efforts to develop novel antibiotics. Moreover, recent work reveals (...) the existence of an undiscovered alternate route for bringing lipoproteins to the OM. Here, lipoprotein transport mechanisms, and the quality control systems that underpin them, is re-examined in context of their diversity. All essential outer membrane assembly machines require lipoproteins to function. Hence, the transport mechanisms supplying these lipoproteins are critical for maintaining the integrity of the outer membrane barrier against antibiotics. Lipoprotein transport strategies of diverse Gram-negative bacteria will be reviewed in the context of recent discoveries. (shrink)

Defined as the ability to understand and share others' feelings and suffering, empathy seems to come naturally to mind when we consider Simone Weil's life and works. If this concept doesn't explicitly appear in her writings, "pity", "sympathy" and "compassion" are pervasive: the purpose of this paper is to demonstrate how these notions converge on the contemporary understanding of "empathy". Since the turn of the century, this concept has known such a development that it has become difficult to clearly identify (...) its object, and to appreciate its ethical value. To study Simone Weil's works from the angle of empathy offers both a new approach of the concept, and a very relevant point of view to put in light the great continuity between all the fields of the philosopher's thought. Our main hypothesis is that the weilian theory of empathy is based on the idea of "transposition", a process that allows someone to transport himself into another person, and from the natural to the supernatural dimension. It is in this last dimension that Simone Weil can found intersubjectivity, and solve the ethical problem of empathy: the right distance between the Self and the Other. (shrink)

We all know that problems of transportation and allocation appear frequently in practical life. We need to transfer materials from production centers to consumption centers to secure the areas’ need for the transported material or allocate machines or people to do a specific job at the lowest cost, or in the shortest time. We know that the cost factors Time is one of the most important factors that decision-makers care about because it plays an “important” role in many of the (...) practical and scientific issues that we face in our daily lives, and we need careful study to enable us to avoid losses. For this, the linear programming method was used, which is one of the research methods. Processes, where the problem data is converted into a linear mathematical model for which the optimal solution achieves the desired goal. Since these models are linear models, we can solve them using the direct simplex method and its modifications, but the specificity that these models enjoy has enabled scholars and researchers to find special methods that help us in obtaining the optimal solution. Whatever the method used, the goal is to determine the number of units transferred from any material from production centers to consumption centers, or to allocate a machine or person to do a job so that the cost or time is as short as possible. These issues were addressed according to classical logic, but the ideal solution was a specific value appropriate to the conditions in which the data was collected and does not take into account the changes that may occur in the work environment. In order to obtain results that are more accurate and enjoy a margin of freedom, we present in this book a study of transport issues and neutrosophic allocation issues and some methods for solving them. By neutrosophic issues we mean These are the problems in which the data are neutrosophic values, i.e. the required quantities and the available quantities. (shrink)

Citrate, an organic trivalent anion, is a major substrate for generation of energy in most cells. It is produced in mitochondria and used either in the Krebs' cycle or released into cytoplasm through a specific mitochondrial carriers. Citrate can also be taken up from blood through different plasma membrane transporters. In the cytoplasm, citrate can be used ultimately for fatty acid synthesis, which is increased in cancer cells. Here, we review the ways in which citrate can be transported and discuss (...) the changes in transport and metabolism that occur in cancer cells. The primary focus is on the prostate gland, which is known to produce and release large amounts of citrate during its normal secretory function. The significant changes that occur in citrate‐related metabolism and transport in prostate cancer are the second focus. This review strives to relate these mechanisms to molecular biology on the one hand and to clinical applications on the other. (shrink)

The essential biological processes that sustain life are catalyzed by protein nano-engines, which maintain living systems in far-from-equilibrium ordered states. To investigate energetic processes in proteins, we have analyzed the system of generalized Davydov equations that govern the quantum dynamics of multiple amide I exciton quanta propagating along the hydrogen-bonded peptide groups in α-helices. Computational simulations have confirmed the generation of moving Davydov solitons by applied pulses of amide I energy for protein α-helices of varying length. The stability and mobility (...) of these solitons depended on the uniformity of dipole-dipole coupling between amide I oscillators, and the isotropy of the exciton-phonon interaction. Davydov solitons were also able to quantum tunnel through massive barriers, or to quantum interfere at collision sites. The results presented here support a nontrivial role of quantum effects in biological systems that lies beyond the mechanistic support of covalent bonds as binding agents of macromolecular structures. Quantum tunneling and interference of Davydov solitons provide catalytically active macromolecular protein complexes with a physical mechanism allowing highly efficient transport, delivery, and utilization of free energy, besides the evolutionary mandate of biological order that supports the existence of such genuine quantum phenomena, and may indeed demarcate the quantum boundaries of life. (shrink)

A recently developed formalism which gives a unified picture of the linear transport of moving frames is extended to include a particular type of transport under the 10-parameter Poincaré group. The frame coordinates are expressed in a 5 × 5 matrix representation which includes the position four-vector plus orthonormal tetrads for the internal coordinates. This provides a general description of the kinematics of physical systems which can be represented by moving frames. Several examples are given, including systems moving (...) with spin and Zitterbewegung along both timelike and null paths. The concept of boost or Poincaré momentum is related to system kinematics. Lagrangians of these systems are also discussed. (shrink)

Adenosine transport in cultured human umbilical vein endothelial cells (HUVEC) was characterized and shown to be mediated by a single facilitated diffusion mechanism. Initial rates of adenosine influx at 22 degrees C were saturable [apparent Michaelis constant, 69 +/- 10 mu M; maximum velocity (V-max), 600 +/- 70 pmol.10(6) cells(-1).s(-1)] and inhibited by nitrobenzylthioinosine (NBMPR). Formycin B had an unusually high affinity [inhibitory constant K-i), 18 +/- 4.3 mu M], whereas inosine had a low affinity (K-i, 440 +/- 68 (...) mu M) and nucleobases were without effect on adenosine influx. The number of transporters (1.2 x 10(6) sites/cell) was estimated by NBMPR equilibrium binding (apparent dissociation constant, 0.11 +/- 0.01 nM; maximum binding, 2.0 +/- 0.15 pmol/10(6) cells). In addition, we compared these endothelial cells with those obtained from cords from pregnancies complicated by diabetes (HUVEC-D), since embriopathy may occur in these conditions. HUVEC-D exhibited a 2.3-fold reduction in both the V-max for adenosine influx and the maximum number of NBMPR binding sites (260 +/- 40 pmol.10(6) cells(-1).s(-1) and 0.86 +/- 0.08 pmol/10(6) cells, respectively). However, the turnover number for each nucleoside transporter in normal and diabetic HUVEC was similar (approximate to 300 adenosine molecules/s). Adenosine metabolism at 10 mu M in HUVEC-D was modified compared with normal cells. Intracellular phosphorylation (> 90%) was the predominant pathway in normal HUVEC, whereas in HUVEC-D, substantial levels of adenine and adenosine were detected. The present results demonstrate therefore the downregulation of the NBMPR-sensitive nucleoside transporter and changes in adenosine metabolism in HUVEC from diabetic pregnancies. (shrink)

In recent years, philosophical examinations of automated vehicles have progressed far beyond initial concerns over the ethical decisions that pertain to programming in the event of a crash. In turn, this paper moves in that direction, focusing on the motivations behind efforts to implement driverless vehicles into urban settings. The author argues that the many perceived benefits of these technologies yield a received view of automated vehicles. This position holds that driverless vehicles can solve most if not all urban mobility (...) issues. However, the problem with such an outlook is that it lends itself to transportation planning for automated vehicles, rather than using them as part of planning efforts that could serve urban mobility. Due to this condition, present efforts aimed at improving transportation systems should resist dogmatic thinking. Instead, they should focus on goals that keep topics such a human flourishing, sustainability, and transportation justice firmly in view. (shrink)

In all domains of life, transmembrane proteins from the ATP‐binding cassette (ABC) transporter family drive the translocation of diverse substances across lipid bilayers. In pathogenic fungi, the ABC transporters of the pleiotropic drug resistance (PDR) subfamily confer antibiotic resistance and so are of interest as therapeutic targets. They also drive the quest for understanding how ABC transporters can generally accommodate such a wide range of substrates. The Pdr5 transporter from baker's yeast is representative of the PDR group and, ever since (...) its discovery more than 30 years ago, has been the subject of extensive functional analyses. A new perspective of these studies has been recently provided in the framework of the first electron cryo‐microscopy structures of Pdr5, as well as emergent applications of machine learning in the field. Taken together, the old and the new developments have been used to propose a mechanism for the transport process in PDR proteins. This mechanism involves a “flippase” step that moves the substrates from one leaflet of the bilayer to the other, as a central element of cellular efflux. (shrink)

Drugs targeting a single TK/RTK in the treatment of solid cancers has not had the same success seen in blood cancers. This is, in part, due to acquired resistance in solid cancers arising from a range of mechanisms including the upregulation of compensatory RTK signalling. Rather than attempting to inhibit individual compensatory RTK—requiring knowledge of which RTKs are upregulated in any given tumour—strategies to universally inhibit signalling from multiple RTKs may represent an effective alternative. Endosomal trafficking of RTKs is a (...) common conduit that can regulate signalling from multiple RTKs simultaneously. As such, we posit that targeting endosomal trafficking—in particular, aberrant post‐translational modifications in cancers that contribute to dysregulated endosomal trafficking—could inhibit oncogenic signalling driven by multiple RTKs and pave the way for the development of a novel class of inhibitors that shift the trafficking of RTKs to inhibit tumour growth. (shrink)

We all know that problems of transportation and allocation appear frequently in practical life. We need to transfer materials from production centers to consumption centers to secure the areas’ need for the transported material or allocate machines or people to do a specific job at the lowest cost, or in the shortest time. We know that the cost factors Time is one of the most important factors that decision-makers care about because it plays an “important” role in many of the (...) practical and scientific issues that we face in our daily lives, and we need careful study to enable us to avoid losses. For this, the linear programming method was used, which is one of the research methods. Processes, where the problem data is converted into a linear mathematical model for which the optimal solution achieves the desired goal. Since these models are linear models, we can solve them using the direct simplex method and its modifications, but the specificity that these models enjoy has enabled scholars and researchers to find special methods that help us in obtaining the optimal solution. Whatever the method used, the goal is to determine the number of units transferred from any material from production centers to consumption centers, or to allocate a machine or person to do a job so that the cost or time is as short as possible. These issues were addressed according to classical logic, but the ideal solution was a specific value appropriate to the conditions in which the data was collected and does not take into account the changes that may occur in the work environment. In order to obtain results that are more accurate and enjoy a margin of freedom, we present in this book a study of transport issues and neutrosophic allocation issues and some methods for solving them. By neutrosophic issues we mean These are the problems in which the data are neutrosophic values, i.e. the required quantities and the available quantities. (shrink)

When cells are starved of their substrate, many nutrient transporters are induced. These undergo rapid endocytosis and redirection of their intracellular trafficking when their substrate becomes available again. The discovery that some of these transporters also act as receptors, or transceptors, suggests that at least part of the sophisticated controls governing the trafficking of these proteins has to do with their signaling function rather than with control of transport. In yeast, the general amino acid permease Gap1 mediates signaling to (...) the protein kinase A pathway. Its endocytic internalization and intracellular trafficking are subject to amino acid control. Other nutrient transceptors controlling this signal transduction pathway appear to be subject to similar trafficking regulation. Transporters with complex regulatory control have also been suggested to function as transceptors in other organisms. Hence, precise regulation of intracellular trafficking in nutrient transporters may be related to the need for tight control of nutrient‐induced signaling. (shrink)

The introduction of new medical technologies into a developing country is usually greeted with enthusiasm as the possible benefits become an object of great anticipation and provide new hope for therapy or relief. The prompt utilization of new discoveries and inventions by a medical practitioner serves as a positive indicator of high standing in the professional community. But the transfer of medical technology also involves a transfer of concomitant values. There is a danger that, in the process of adopting a (...) particular technology, the user takes for granted the general utility and desirability of the implements and procedures under consideration without recognizing the socio‐cultural peculiarities of the adopting country. A sensitivity to the social conditions and cultural traditions is important so that the emergence of new values can be examined critically and the transfer of necessary technology can be effected smoothly. In the Philippines, efforts to boost patronage of transplant technology appear to have overlooked this need for socio‐cultural sensitivity. Legislative fiat cannot be used to override deep‐seated values. There is a need to be more sensitive to the possible confrontation of values that the transfer of technology brings in order to avoid the erosion of indigenous socio‐cultural values and minimize the intrusiveness of beneficial medical technology. (shrink)

The energy transport in one-dimensional nonlinear systems is discussed. By numerically studying a model system, we verify the Fourier heat law on purely dynamical grounds and we compute the coefficient of thermal conductivity K. The same value ofK is independently obtained by use of the Green-Kubo formalism.

A major problem in the treatment of cancer is the specific targeting of anti‐tumor drugs to these abnormal cells. Ideally, such a drug should act over short distances to minimize damage to healthy cells, and target subcellular compartments that have the highest sensitivity to the drug. Photosensitizers, alpha‐emitting radionuclides and many other medicines could be considered as such drugs if they possessed cellular and subcellular specificity. The author describes a novel approach of using modular recombinant transporters to target photosensitizers and (...) alpha‐emitting radionuclides to the nucleus, where their action is most pronounced, of cancer cells. Photosensitizer‐transporter conjugates have up to 3000 times greater efficacy than free photosensitizers and display cell specificity in contrast to free photosensitizers. Alpha‐emitting radionuclides, conjugated with the modular transporters, acquired similar properties. The different modules of the transporters are interchangeable, meaning that they can be tailored for particular applications. BioEssays 30:278–287, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

We question Baumard's underlying assumption that humans have a propensity to innovate. Affordable transportation and energy underpinned the Industrial Revolution, making mass production/consumption possible. Although we cannot accept Baumard's thesis on the Industrial Revolution, it may help explain why complexity and innovation increase rapidly in the context of abundant energy.

A Controlled Not variant of the standard quantum teleportation protocol affords a step-by-step analysis of what is, or can be said to be, achieved in the process in either location. Dominant interpretations of what quantum teleportation consists in and implies are reviewed in this light. Being mindful of the statistical significance of the terms and operations involved, as well as awareness of classical analogies, can help sort out what is specifically quantum-mechanical, and what is not, in so-called teleportation. What the (...) latter achieves appears to be the transmission, without the involvement of mysterious channels, of what a quantum state encapsulates: the multitiered probabilistic characterization of a given preparation, which might be all we can possibly know about a physical system in a given experimental situation. (shrink)

The American Journal of Bioethics, Volume 12, Issue 7, Page 19-21, July 2012.

Peroxisomal matrix proteins are synthesized on cytosolic ribosomes and rapidly transported into the organelle by a complex machinery. The data gathered in recent years suggest that this machinery operates through a syringe-like mechanism, in which the shuttling receptor PEX5 − the “plunger” − pushes a newly synthesized protein all the way through a peroxisomal transmembrane protein complex − the “barrel” − into the matrix of the organelle. Notably, insertion of cargo-loaded receptor into the “barrel” is an ATP-independent process, whereas extraction (...) of the receptor back into the cytosol requires its monoubiquitination and the action of ATP-dependent mechanoenzymes. Here, we review the main data behind this model. The peroxin PEX5 is the peroxisomal matrix protein receptor. It shuttles between the cytosol and the organelle membrane, where it gets inserted into the docking/translocation module, thus pushing the cargo-protein into the peroxisome lumen. Resetting the system involves PEX5 monoubiquitination and its extraction from the membrane by the AAA-ATPases, PEX1/PEX6. (shrink)

Most metazoan organisms have evolved a mildly acidified and calcium diminished sorting hub in the early secretory pathway commonly referred to as the Endoplasmic Reticulum‐Golgi intermediate compartment (ERGIC). These membranous vesicular‐tubular clusters are found tightly juxtaposed to ER subdomains that are competent for the production of COPII‐coated transport carriers. In contrast to many unicellular systems, metazoan COPII carriers largely transit just a few hundred nanometers to the ERGIC, prior to COPI‐dependent transport on to the cis‐Golgi. The mechanisms underlying (...) formation and maintenance of ERGIC membranes are poorly defined. However, recent evidence suggests an important role for Trk‐fused gene (TFG) in regulating the integrity of the ER/ERGIC interface. Moreover, in the absence of cytoskeletal elements to scaffold tracks on which COPII carriers might move, TFG appears to promote anterograde cargo transport by locally tethering COPII carriers adjacent to ERGIC membranes. This action, regulated in part by the intrinsically disordered domain of TFG, provides sufficient time for COPII coat disassembly prior to heterotypic membrane fusion and cargo delivery to the ERGIC. -/- . (shrink)

Physiological studies show that the driving force for long distance transport and the control of nutrient movement in plants resides largely in the regulated, membrane transport of a few carbohydrates, principally sucrose. The evidence is reviewed here and biochemical studies on sucrose carrier proteins are discussed.

The complex spectral representation of the Liouville operator introduced by Prigogine and others is applied to moderately dense gases interacting through hard-core potentials in arbitrary d-dimensional spaces. Kinetic equations near equilibrium are constructed in each subspace as introduced in the spectral decomposition for collective, renormalized reduced distribution functions. Our renormalization is a nonequilibrium effect, as the renormalization effect disappears at equilibrium. It is remarkable that our renormalized functions strictly obey well-defined Markovian kinetic equations for all d, even though the ordinary (...) distribution functions obey nonMarkovian equations with memory effects. One can now define transport coefficients associated to the collective modes for all dimensional systems including d = 2. Our formulation hence provides a microscopic meaning of the macroscopic transport theory. Moreover, this gives an answer to the long-standing question whether or not transport equations exist in two-dimensional systems. The non-Markovian effects for the ordinary distribution function, such as the long-time tails for arbitrary n-mode coupling, are estimated by superposition of the Markovian evolutions of the dressed distribution functions. (shrink)

This article attempts to study cost minimizing multi-objective fractional solid transportation problem with fuzzy cost coefficients c ˜ i j k r {\tilde{c}}_{ijk}^{r}, fuzzy supply quantities a ˜ i {\tilde{a}}_{i}, fuzzy demands b ˜ j {\tilde{b}}_{j}, and/or fuzzy conveyances e ˜ k {\tilde{e}}_{k}. The fuzzy efficient concept is introduced in which the crisp efficient solution is extended. A necessary and sufficient condition for the solution is established. Fuzzy geometric programming approach is applied to solve the crisp problem by defining membership (...) function so as to obtain the optimal compromise solution of a multi-objective two-stage problem. A linear membership function for the objective function is defined. The stability set of the first kind is defined and determined. A numerical example is given for illustration and to check the validity of the proposed approach. (shrink)