The spectrin-based membrane skeleton as a membrane protein-sorting machine

1996 ◽  
Vol 270 (5) ◽  
pp. C1263-C1270 ◽  
Author(s):  
K. A. Beck ◽  
W. J. Nelson
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Cell Function ◽  
Protein Sorting ◽  
Membrane Skeleton ◽  
Membrane Domains ◽  
Sorting Machine ◽  
Membrane Compartments ◽  
Molecular Machinery ◽  
Distinct Membrane

Normal cell function is dependent on the existence of membrane compartments that have unique populations of membrane proteins. Sorting of membrane proteins forms the basis for the biogenesis of distinct membrane compartments. There are many examples of membrane protein-sorting events in cells, but the molecular machinery involved is poorly understood. We discuss characteristics of a putative membrane protein-sorting machine and show that the spectrin-based membrane skeleton conforms to these characteristics. The spectrin-based membrane skeleton is a submembranous, spatially limited, two-dimensional lattice that binds a subset of membrane proteins. These properties allow the membrane skeleton to facilitate the formation of distinct membrane domains and thus reveal its potential as a membrane protein-sorting machine.

Protein Sorting in Healthy and Diseased Photoreceptors

2019 ◽  
Vol 5 (1) ◽  
pp. 73-98 ◽  
Author(s):  
Yoshikazu Imanishi
Keyword(s):  
Signal Transduction ◽  
Membrane Protein ◽  
Outer Segment ◽  
Protein Sorting ◽  
Rods And Cones ◽  
Retinal Photoreceptor ◽  
Photoreceptor Neurons ◽  
Cellular Compartments ◽  
G Protein Coupled ◽  
Distinct Membrane

Rods and cones are retinal photoreceptor neurons required for our visual sensation. Because of their highly polarized structures and well-characterized processes of G protein–coupled receptor–mediated phototransduction signaling, these photoreceptors have been excellent models for studying the compartmentalization and sorting of proteins. Rods and cones have a modified ciliary compartment called the outer segment (OS) as well as non-OS compartments. The distinct membrane protein compositions between OS and non-OS compartments suggest that the OS is separated from the rest of the cellular compartments by multiple barriers or gates that are selectively permissive to specific cargoes. This review discusses the mechanisms of protein sorting and compartmentalization in photoreceptor neurons. Proper sorting and compartmentalization of membrane proteins are required for signal transduction and transmission. This review also discusses the roles of compartmentalized signaling, which is compromised in various retinal ciliopathies.

scholarly journals Plasma Membrane Protein Nce102 Modulates Morphology and Function of the Yeast Vacuole

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1476
Author(s):  
Katarina Vaskovicova ◽  
Petra Vesela ◽  
Jakub Zahumensky ◽  
Dagmar Folkova ◽  
Maria Balazova ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Vacuolar Membrane ◽  
Yeast Culture ◽  
Membrane Domains ◽  
Biological Functions ◽  
Plasma Membrane Protein ◽  
Cell Architecture ◽  
And Function

Membrane proteins are targeted not only to specific membranes in the cell architecture, but also to distinct lateral microdomains within individual membranes to properly execute their biological functions. Yeast tetraspan protein Nce102 has been shown to migrate between such microdomains within the plasma membrane in response to an acute drop in sphingolipid levels. Combining microscopy and biochemistry methods, we show that upon gradual ageing of a yeast culture, when sphingolipid demand increases, Nce102 migrates from the plasma membrane to the vacuole. Instead of being targeted for degradation it localizes to V-ATPase-poor, i.e., ergosterol-enriched, domains of the vacuolar membrane, analogous to its plasma membrane localization. We discovered that, together with its homologue Fhn1, Nce102 modulates vacuolar morphology, dynamics, and physiology. Specifically, the fusing of vacuoles, accompanying a switch of fermenting yeast culture to respiration, is retarded in the strain missing both proteins. Furthermore, the absence of either causes an enlargement of ergosterol-rich vacuolar membrane domains, while the vacuoles themselves become smaller. Our results clearly show decreased stability of the V-ATPase in the absence of either Nce102 or Fhn1, a possible result of the disruption of normal microdomain morphology of the vacuolar membrane. Therefore, the functionality of the vacuole as a whole might be compromised in these cells.

scholarly journals VIP21, a 21-kD membrane protein is an integral component of trans-Golgi-network-derived transport vesicles.

1992 ◽  
Vol 118 (5) ◽  
pp. 1003-1014 ◽  
Author(s):  
T V Kurzchalia ◽  
P Dupree ◽  
R G Parton ◽  
R Kellner ◽  
H Virta ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Integral Membrane Protein ◽  
Cellular Membrane ◽  
Integral Membrane Proteins ◽  
Membrane Domains ◽  
Transport Vesicles ◽  
Vesicular Carriers ◽  
Molecular Machinery ◽  
Golgi Network

In simple epithelial cells, apical and basolateral proteins are sorted into separate vesicular carriers before delivery to the appropriate plasma membrane domains. To dissect the putative sorting machinery, we have solubilized Golgi-derived transport vesicles with the detergent CHAPS and shown that an apical marker, influenza haemagglutinin (HA), formed a large complex together with several integral membrane proteins. Remarkably, a similar set of CHAPS-insoluble proteins was found after solubilization of a total cellular membrane fraction. This allowed the cloning of a cDNA encoding one protein of this complex, VIP21 (Vesicular Integral-membrane Protein of 21 kD). The transiently expressed protein appeared on the Golgi-apparatus, the plasma membrane and vesicular structures. We propose that VIP21 is a component of the molecular machinery of vesicular transport.

scholarly journals Epithelial Cell Polarity From the Outside Looking In

Physiology ◽  
2003 ◽  
Vol 18 (4) ◽  
pp. 143-146 ◽  
Author(s):  
W. James Nelson
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cell ◽  
Membrane Proteins ◽  
Cell Polarity ◽  
Protein Sorting ◽  
Membrane Domains ◽  
Epithelial Cell Polarity

Epithelial cell polarity may be regulated by protein sorting in the Golgi and delivery to different membrane domains, a view from the inside looking out. But from the outside looking in, cell adhesion may be required first to establish sites for delivery, retention, and separation of membrane proteins, and delivery of presorted proteins from the Golgi subsequently reinforces and maintains different membrane domains.

scholarly journals Membrane protein mobility depends on the length of extra-membrane domains and on the protein concentration

Soft Matter ◽  
2015 ◽  
Vol 11 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Gernot Guigas ◽  
Matthias Weiss
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Protein Concentration ◽  
Membrane Domains ◽  
Membrane Anchor ◽  
Protein Mobility ◽  
P Diffusion

Diffusion of membrane proteins is not only determined by the membrane anchor friction but also by the overall concentration of proteins and the length of their extra-membrane domains.

scholarly journals Erythrocyte membrane changes of chorea-acanthocytosis are the result of altered Lyn kinase activity

Blood ◽  
2011 ◽  
Vol 118 (20) ◽  
pp. 5652-5663 ◽  
Author(s):  
Lucia De Franceschi ◽  
Carlo Tomelleri ◽  
Alessandro Matte ◽  
Anna Maria Brunati ◽  
Petra H. Bovee-Geurts ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Neurodegenerative Disorder ◽  
Protein Composition ◽  
Membrane Skeleton ◽  
Band 3 ◽  
Diagnostic Feature ◽  
Lyn Kinase ◽  
Rbc Membrane ◽  
Membrane Changes

Abstract Acanthocytic RBCs are a peculiar diagnostic feature of chorea-acanthocytosis (ChAc), a rare autosomal recessive neurodegenerative disorder. Although recent years have witnessed some progress in the molecular characterization of ChAc, the mechanism(s) responsible for generation of acanthocytes in ChAc is largely unknown. As the membrane protein composition of ChAc RBCs is similar to that of normal RBCs, we evaluated the tyrosine (Tyr)–phosphorylation profile of RBCs using comparative proteomics. Increased Tyr phosphorylation state of several membrane proteins, including band 3, β-spectrin, and adducin, was noted in ChAc RBCs. In particular, band 3 was highly phosphorylated on the Tyr-904 residue, a functional target of Lyn, but not on Tyr-8, a functional target of Syk. In ChAc RBCs, band 3 Tyr phosphorylation by Lyn was independent of the canonical Syk-mediated pathway. The ChAc-associated alterations in RBC membrane protein organization appear to be the result of increased Tyr phosphorylation leading to altered linkage of band 3 to the junctional complexes involved in anchoring the membrane to the cytoskeleton as supported by coimmunoprecipitation of β-adducin with band 3 only in ChAc RBC-membrane treated with the Lyn-inhibitor PP2. We propose this altered association between membrane skeleton and membrane proteins as novel mechanism in the generation of acanthocytes in ChAc.

TMCC3 localizes at the three-way junctions for the proper tubular network of the endoplasmic reticulum

2019 ◽  
Vol 476 (21) ◽  
pp. 3241-3260
Author(s):  
Sindhu Wisesa ◽  
Yasunori Yamamoto ◽  
Toshiaki Sakisaka
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Mammalian Cells ◽  
Coiled Coil ◽  
Transmembrane Domains ◽  
Domain Family ◽  
Coiled Coil Domain ◽  
U2os Cells ◽  
Er Membrane

The tubular network of the endoplasmic reticulum (ER) is formed by connecting ER tubules through three-way junctions. Two classes of the conserved ER membrane proteins, atlastins and lunapark, have been shown to reside at the three-way junctions so far and be involved in the generation and stabilization of the three-way junctions. In this study, we report TMCC3 (transmembrane and coiled-coil domain family 3), a member of the TEX28 family, as another ER membrane protein that resides at the three-way junctions in mammalian cells. When the TEX28 family members were transfected into U2OS cells, TMCC3 specifically localized at the three-way junctions in the peripheral ER. TMCC3 bound to atlastins through the C-terminal transmembrane domains. A TMCC3 mutant lacking the N-terminal coiled-coil domain abolished localization to the three-way junctions, suggesting that TMCC3 localized independently of binding to atlastins. TMCC3 knockdown caused a decrease in the number of three-way junctions and expansion of ER sheets, leading to a reduction of the tubular ER network in U2OS cells. The TMCC3 knockdown phenotype was partially rescued by the overexpression of atlastin-2, suggesting that TMCC3 knockdown would decrease the activity of atlastins. These results indicate that TMCC3 localizes at the three-way junctions for the proper tubular ER network.

Simulation studies of the interactions between membrane proteins and detergents

2005 ◽  
Vol 33 (5) ◽  
pp. 910-912 ◽  
Author(s):  
P.J. Bond ◽  
J. Cuthbertson ◽  
M.S.P. Sansom
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Self Assembly ◽  
Kinetic Mechanism ◽  
Coarse Grained ◽  
Simulation Studies ◽  
High Resolution Data ◽  
Biologically Relevant ◽  
Structure And Dynamics ◽  
Detergent Interactions

Interactions between membrane proteins and detergents are important in biophysical and structural studies and are also biologically relevant in the context of folding and transport. Despite a paucity of high-resolution data on protein–detergent interactions, novel methods and increased computational power enable simulations to provide a means of understanding such interactions in detail. Simulations have been used to compare the effect of lipid or detergent on the structure and dynamics of membrane proteins. Moreover, some of the longest and most complex simulations to date have been used to observe the spontaneous formation of membrane protein–detergent micelles. Common mechanistic steps in the micelle self-assembly process were identified for both α-helical and β-barrel membrane proteins, and a simple kinetic mechanism was proposed. Recently, simplified (i.e. coarse-grained) models have been utilized to follow long timescale transitions in membrane protein–detergent assemblies.

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