Subcellular localization of G-proteins in primary-cultured mouse preadipocytes and adipocytes.
The subcellular localization of G5 alpha, Gi alpha 1&2, Gi alpha 3, and G beta was studied in primary-cultured undifferentiated and differentiated, lipid replete, adipose cells. The results show a distinct distribution for each of these G-proteins and differences between differentiated and undifferentiated cells. All the G-proteins examined had a cytoplasmic localization; only Gi alpha 1 and 2 showed a significant colocalization with the plasma membrane and this only in differentiated cells. Most studies using cells in culture have reported an intracellular localization for G-proteins, whereas in tissue sections the localization has been reported to be largely with the plasma membrane, with some intracellular localization. The results suggest that the cell-cell interactions or the specific geometry imposed by culture conditions favor the intracellular compared to peripheral localization of G-proteins. Alternately, the posttranslational modifications necessary for G-protein insertion in the plasma membrane may be deficient in cultured cells.
Bégin-Heick
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Department of Biochemistry, University of Ottawa, Ontario, Canada. nicoleb@coupo.cou.on.ca
Black
M A
MA
Gaffield
J
J
Cadrin
M
M
D000262:Adenylyl Cyclases / Q000378:metabolism; D017667:Adipocytes / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure*; D000818:Animals; D002454:Cell Differentiation; D002462:Cell Membrane / Q000737:chemistry; D002467:Cell Nucleus / Q000737:chemistry; D002478:Cells, Cultured; D003593:Cytoplasm / Q000737:chemistry; D005455:Fluorescent Antibody Technique; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000032:analysis; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000032:analysis; D019204:GTP-Binding Proteins / Q000032:analysis*; D005993:Glycerolphosphate Dehydrogenase / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
D005993:Glycerolphosphate Dehydrogenase; D019204:GTP-Binding Proteins; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D019205:GTP-Binding Protein alpha Subunits, Gs; D000262:Adenylyl Cyclases