Pericentriolar targeting of GDP-dissociation inhibitor isoform 2
| Autor: | A, Shisheva, S J, Doxsey, J M, Buxton, M P, Czech |
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| Rok vydání: | 1995 |
| Předmět: |
Octoxynol
Recombinant Fusion Proteins rab3 GTP-Binding Proteins Detergents Molecular Sequence Data Golgi Apparatus Mitosis CHO Cells Cyclopentanes Transfection Proto-Oncogene Proteins c-myc Mice Cricetulus Cytosol GTP-Binding Proteins Cricetinae Chlorocebus aethiops Animals Amino Acid Sequence Antigens Interphase Cell Line Transformed Centrioles Guanine Nucleotide Dissociation Inhibitors Centrosome Brefeldin A Nocodazole Biological Transport Cell Differentiation 3T3 Cells Intracellular Membranes Fibroblasts Endocytosis Adipose Tissue Microscopy Fluorescence |
| Zdroj: | European journal of cell biology. 68(2) |
| ISSN: | 0171-9335 |
| Popis: | Cellular mechanisms for regulating membrane movements appear to involve small GTPases of the Rab subfamily. Binding of GDP-bound Rab proteins to donor membranes and their release from target membranes appear to be regulated by GDP-dissociation inhibitor (GDI) protein isoforms. Previous work showed strikingly higher levels of GDI-2 than GDI-1 fractionate with total membranes of cultured cells and are visualized in the perinuclear region in 3T3-L1 adipocytes. Here we report that GDI-2-containing structural elements are concentrated predominantly in the pericentriolar area in interphase CHO-T cells and differentiated 3T3-L1 adipocytes based on colocalization of GDI-2 and the centrosomal marker pericentrin. This finding is documented by both immunofluorescence and immunoelectron microscopy. Expressed c-Myc-tagged GDI-2 in transfected COS-7 cells targets to the same region. During mitotic resolution of the centrosome into two identifiable foci in CHO-T cells, GDI-2 containing structures remain intact and also resolve into two regions surrounding the centrosome. Dissociation of pericentriolar GDI-2 from the Golgi markers beta-COP and lectin receptors was apparent upon brefeldin A treatment of 3T3-L1 adipocytes or CHO-T cells. The integrity of pericentriolar GDI-2-binding elements was not disrupted by either brief Triton X-100 extraction or microtubule cytoskeletal disassembly, achieved with nocodazole. These data demonstrate the presence of highly ordered, detergent-resistant GDI-2-specific structural elements around the centrosome and indicate functional differences for the GDI-1 and GDI-2 protein isoforms. The results suggest the presence of selective GDI-2 acceptors in this region and a possible role of pericentriolar GDI-2 in membrane recycling. |
| Databáze: | OpenAIRE |
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