Biomaterial Database

100-kD proteins of Golgi- and trans-Golgi network-associated coated vesicles have related but distinct membrane binding properties. 1992

D H Wong, and F M Brodsky

Department of Pharmacy, School of Pharmacy, University of California San Francisco 94143-0446.

The 100-110-kD proteins (alpha-, beta-, beta'-, and gamma-adaptins) of clathrin-coated vesicles and the 110-kD protein (beta-COP) of the nonclathrin-coated vesicles that mediate constitutive transport through the Golgi have homologous protein sequences. To determine whether homologous processes are involved in assembly of the two types of coated vesicles, the membrane binding properties of their coat proteins were compared. After treatment of MDBK cells with the fungal metabolite Brefeldin A (BFA), beta-COP was redistributed to the cytoplasm within 15 s, gamma-adaptin and clathrin in the trans-Golgi network (TGN) dispersed within 30 s, but the alpha-adaptin and clathrin present on coated pits and vesicles derived from the plasma membrane remained membrane associated even after a 15-min exposure to BFA. In PtK1 cells and MDCK cells, BFA did not affect beta-COP binding or Golgi morphology but still induced redistribution of gamma-adaptin and clathrin from TGN membranes to the cytoplasm. Thus BFA affects the binding of coat proteins to membranes in the Golgi region (Golgi apparatus and TGN) but not plasma membranes. However, the Golgi binding interactions of beta-COP and gamma-adaptin are distinct and differentially sensitive to BFA. BFA treatment did not release gamma-adaptin or clathrin from purified clathrin-coated vesicles, suggesting that their distribution to the cytoplasm after BFA treatment of cells was due to interference with their rebinding to TGN membranes after a normal cycle of disassembly. This was confirmed using an in vitro assay in which gamma-adaptin binding to TGN membranes was blocked by BFA and enhanced by GTP gamma S, similar to the binding of beta-COP to Golgi membranes. These results suggest the involvement of GTP-dependent proteins in the association of the 100-kD coat proteins with membranes in the Golgi region of the cell.

UI	MeSH Term	Description	Entries
D007425	Intracellular Membranes	Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Membranes, Intracellular,Intracellular Membrane,Membrane, Intracellular
D008869	Microtubule-Associated Proteins	High molecular weight proteins found in the MICROTUBULES of the cytoskeletal system. Under certain conditions they are required for TUBULIN assembly into the microtubules and stabilize the assembled microtubules.	Ensconsin,Epithelial MAP, 115 kDa,Epithelial Microtubule-Associate Protein, 115 kDa,MAP4,Microtubule Associated Protein,Microtubule Associated Protein 4,Microtubule Associated Protein 7,Microtubule-Associated Protein,Microtubule-Associated Protein 7,E-MAP-115,MAP1 Microtubule-Associated Protein,MAP2 Microtubule-Associated Protein,MAP3 Microtubule-Associated Protein,Microtubule Associated Proteins,Microtubule-Associated Protein 1,Microtubule-Associated Protein 2,Microtubule-Associated Protein 3,7, Microtubule-Associated Protein,Associated Protein, Microtubule,E MAP 115,Epithelial Microtubule Associate Protein, 115 kDa,MAP1 Microtubule Associated Protein,MAP2 Microtubule Associated Protein,MAP3 Microtubule Associated Protein,Microtubule Associated Protein 1,Microtubule Associated Protein 2,Microtubule Associated Protein 3,Microtubule-Associated Protein, MAP1,Microtubule-Associated Protein, MAP2,Microtubule-Associated Protein, MAP3,Protein 7, Microtubule-Associated,Protein, Microtubule Associated,Protein, Microtubule-Associated
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D003034	Coated Pits, Cell-Membrane	Specialized regions of the cell membrane composed of pits coated with a bristle covering made of the protein CLATHRIN. These pits are the entry route for macromolecules bound by cell surface receptors. The pits are then internalized into the cytoplasm to form the COATED VESICLES.	Bristle-Coated Pits,Cell-Membrane Coated Pits,Bristle Coated Pits,Bristle-Coated Pit,Cell Membrane Coated Pits,Cell-Membrane Coated Pit,Coated Pit, Cell-Membrane,Coated Pits, Cell Membrane,Pit, Bristle-Coated,Pit, Cell-Membrane Coated,Pits, Bristle-Coated,Pits, Cell-Membrane Coated
D003517	Cyclopentanes	A group of alicyclic hydrocarbons with the general formula R-C5H9.	Cyclopentadiene,Cyclopentadienes,Cyclopentene,Cyclopentenes,Cyclopentane
D003593	Cytoplasm	The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Protoplasm,Cytoplasms,Protoplasms
D005455	Fluorescent Antibody Technique	Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.	Antinuclear Antibody Test, Fluorescent,Coon's Technique,Fluorescent Antinuclear Antibody Test,Fluorescent Protein Tracing,Immunofluorescence Technique,Coon's Technic,Fluorescent Antibody Technic,Immunofluorescence,Immunofluorescence Technic,Antibody Technic, Fluorescent,Antibody Technics, Fluorescent,Antibody Technique, Fluorescent,Antibody Techniques, Fluorescent,Coon Technic,Coon Technique,Coons Technic,Coons Technique,Fluorescent Antibody Technics,Fluorescent Antibody Techniques,Fluorescent Protein Tracings,Immunofluorescence Technics,Immunofluorescence Techniques,Protein Tracing, Fluorescent,Protein Tracings, Fluorescent,Technic, Coon's,Technic, Fluorescent Antibody,Technic, Immunofluorescence,Technics, Fluorescent Antibody,Technics, Immunofluorescence,Technique, Coon's,Technique, Fluorescent Antibody,Technique, Immunofluorescence,Techniques, Fluorescent Antibody,Techniques, Immunofluorescence,Tracing, Fluorescent Protein,Tracings, Fluorescent Protein
D006056	Golgi Apparatus	A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Golgi Complex,Apparatus, Golgi,Complex, Golgi