scholarly journals Flat clathrin lattices: stable features of the plasma membrane

2014 ◽  
Vol 25 (22) ◽  
pp. 3581-3594 ◽  
Author(s):  
Joe Grove ◽  
Daniel J. Metcalf ◽  
Alex E. Knight ◽  
Silène T. Wavre-Shapton ◽  
Tony Sun ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Biology ◽  
Quantitative Imaging ◽  
Fundamental Property ◽  
Coated Pits ◽  
Comprehensive Description ◽  
Superresolution Microscopy ◽  
Chemokine Receptor Ccr5 ◽  
Discrete Populations ◽  
Receptor Ccr5

Clathrin-mediated endocytosis (CME) is a fundamental property of eukaryotic cells. Classical CME proceeds via the formation of clathrin-coated pits (CCPs) at the plasma membrane, which invaginate to form clathrin-coated vesicles, a process that is well understood. However, clathrin also assembles into flat clathrin lattices (FCLs); these structures remain poorly described, and their contribution to cell biology is unclear. We used quantitative imaging to provide the first comprehensive description of FCLs and explore their influence on plasma membrane organization. Ultrastructural analysis by electron and superresolution microscopy revealed two discrete populations of clathrin structures. CCPs were typified by their sphericity, small size, and homogeneity. FCLs were planar, large, and heterogeneous and present on both the dorsal and ventral surfaces of cells. Live microscopy demonstrated that CCPs are short lived and culminate in a peak of dynamin recruitment, consistent with classical CME. In contrast, FCLs were long lived, with sustained association with dynamin. We investigated the biological relevance of FCLs using the chemokine receptor CCR5 as a model system. Agonist activation leads to sustained recruitment of CCR5 to FCLs. Quantitative molecular imaging indicated that FCLs partitioned receptors at the cell surface. Our observations suggest that FCLs provide stable platforms for the recruitment of endocytic cargo.

Pathways for internalization and recycling of the chemokine receptor CCR5

Blood ◽  
2002 ◽  
Vol 99 (3) ◽  
pp. 785-791 ◽  
Author(s):  
Anja Mueller ◽  
Eamonn Kelly ◽  
Philip G. Strange
Keyword(s):  
Cell Surface ◽  
G Protein ◽  
Chemokine Receptor ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Coated Pits ◽  
Early Endosomes ◽  
Chemokine Receptor Ccr5 ◽  
G Protein Coupled ◽  
Receptor Ccr5

Abstract M-tropic human immunodeficiency virus (HIV-1) strains enter the cell after interaction with their receptors, CD4 and the G-protein–coupled chemokine receptor CCR5. The number of cell surface CCR5 molecules is thought to be important in determining the infection rate for HIV. Cell surface CCR5 is dependent on the rate of receptor internalization and recycling. Internalization of G-protein–coupled receptors after agonist activation is thought to occur either through clathrin-coated pits or through caveolae. In this study, the role of these different pathways was investigated in Chinese hamster ovary cells expressing CCR5 using specific inhibitors. Internalization of CCR5 after chemokine treatment was inhibited by sucrose, indicating a role for the clathrin-coated pit pathway. Activation of CCR5 leads to arrestin-2 movement in the cells, providing further evidence for the involvement of clathrin-coated pits. Nystatin and filipin also affected the rate of internalization of CCR5, indicating a role for caveolae. Using inhibitors of vesicle transport in the cell, it was found that the CCR5 recycling pathway is independent of the Golgi apparatus and late endosomes. Protein synthesis is not involved in receptor recovery. It seems likely that after internalization, CCR5 is directed to early endosomes and subsequently recycled to the cell surface.

Changes Occur in Plasma Membrane Turnover when K562 Leukemia Cells are Induced to Differentiate

1982 ◽  
Vol 40 ◽  
pp. 286-287
Author(s):  
L. M. Marshall
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Intracellular Transport ◽  
Parent Cell ◽  
Membrane Turnover ◽  
Coated Pits ◽  
Surface Distribution ◽  
Specific Proteins ◽  
Erythroleukemic Cell ◽  
Specific Membrane

A human erythroleukemic cell line, metabolically blocked in a late stage of erythropoiesis, becomes capable of differentiation along the normal pathway when grown in the presence of hemin. This process is characterized by hemoglobin synthesis followed by rearrangement of the plasma membrane proteins and culminates in asymmetrical cytokinesis in the absence of nuclear division. A reticulocyte-like cell buds from the nucleus-containing parent cell after erythrocyte specific membrane proteins have been sequestered into its membrane. In this process the parent cell faces two obstacles. First, to organize its erythrocyte specific proteins at one pole of the cell for inclusion in the reticulocyte; second, to reduce or abolish membrane protein turnover since hemoglobin is virtually the only protein being synthesized at this stage. A means of achieving redistribution and cessation of turnover could involve movement of membrane proteins by a directional lipid flow. Generation of a lipid flow towards one pole and accumulation of erythrocyte-specific membrane proteins could be achieved by clathrin coated pits which are implicated in membrane endocytosis, intracellular transport and turnover. In non-differentiating cells, membrane proteins are turned over and are random in surface distribution. If, however, the erythrocyte specific proteins in differentiating cells were excluded from endocytosing coated pits, not only would their turnover cease, but they would also tend to drift towards and collect at the site of endocytosis. This hypothesis requires that different protein species are endocytosed by the coated vesicles in non-differentiating than by differentiating cells.

Caveolin-1, galectin-3 and lipid raft domains in cancer cell signalling

2015 ◽  
Vol 57 ◽  
pp. 189-201 ◽  
Author(s):  
Jay Shankar ◽  
Cecile Boscher ◽  
Ivan R. Nabi
Keyword(s):  
Plasma Membrane ◽  
Lipid Rafts ◽  
Cancer Cell ◽  
Cellular Response ◽  
Spatial Organization ◽  
Essential Feature ◽  
Cell Signalling ◽  
Coated Pits ◽  
Signalling Molecules ◽  
Raft Domains

Spatial organization of the plasma membrane is an essential feature of the cellular response to external stimuli. Receptor organization at the cell surface mediates transmission of extracellular stimuli to intracellular signalling molecules and effectors that impact various cellular processes including cell differentiation, metabolism, growth, migration and apoptosis. Membrane domains include morphologically distinct plasma membrane invaginations such as clathrin-coated pits and caveolae, but also less well-defined domains such as lipid rafts and the galectin lattice. In the present chapter, we will discuss interaction between caveolae, lipid rafts and the galectin lattice in the control of cancer cell signalling.

Diverse signalling by different chemokines through the chemokine receptor CCR5

2006 ◽  
Vol 72 (6) ◽  
pp. 739-748 ◽  
Author(s):  
Anja Mueller ◽  
Nasir G. Mahmoud ◽  
Philip G. Strange
Keyword(s):  
Chemokine Receptor ◽  
Chemokine Receptor Ccr5 ◽  
Receptor Ccr5

Inhibition of the Human Chemokine Receptor CCR5 by Variecolin and Variecolol and Isolation of Four New Variecolin Analogues, Emericolins A−D, fromEmericella aurantiobrunnea

2004 ◽  
Vol 67 (10) ◽  
pp. 1681-1684 ◽  
Author(s):  
K. Yoganathan ◽  
Christine Rossant ◽  
Robert P. Glover ◽  
Shugeng Cao ◽  
Jagadese J. Vittal ◽  
...  
Keyword(s):  
Chemokine Receptor ◽  
Chemokine Receptor Ccr5 ◽  
Receptor Ccr5

Inhibition of clathrin-coated pit assembly by an Eps15 mutant

1999 ◽  
Vol 112 (9) ◽  
pp. 1303-1311 ◽  
Author(s):  
A. Benmerah ◽  
M. Bayrou ◽  
N. Cerf-Bensussan ◽  
A. Dautry-Varsat
Keyword(s):  
Plasma Membrane ◽  
Fusion Protein ◽  
Binding Site ◽  
Specific Marker ◽  
Coated Pits ◽  
Receptor Mediated Endocytosis ◽  
Gfp Fusion Protein ◽  
Protein Encoding ◽  
Homology Domains

Recent data have shown that Eps15, a newly identified component of clathrin-coated pits constitutively associated with the AP-2 complex, is required for receptor-mediated endocytosis. However, its precise function remains unknown. Interestingly, Eps15 contains three EH (Eps15-Homology) domains also found in proteins required for the internalization step of endocytosis in yeast. Results presented here show that EH domains are required for correct coated pit targeting of Eps15. Furthermore, when cells expressed an Eps15 mutant lacking EH domains, the plasma membrane punctate distribution of both AP-2 and clathrin was lost, implying the absence of coated pits. This was further confirmed by the fact that dynamin, a GTPase found in coated pits, was homogeneously redistributed on the plasma membrane and that endocytosis of transferrin, a specific marker of clathrin-dependent endocytosis, was strongly inhibited. Altogether, these results strongly suggest a role for Eps15 in coated pit assembly and more precisely a role for Eps15 in the docking of AP-2 onto the plasma membrane. This hypothesis is supported by the fact that a GFP fusion protein encoding the ear domain of (alpha)-adaptin, the AP-2 binding site for Eps15, was efficiently targeted to plasma membrane coated pits.

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