Distribution of polypeptides binding guanosine 5'-[gamma-[35S]thio]triphosphate and anti-(ras protein) antibodies in liver subcellular fractions. Evidence for endosome-specific components.
The subcellular distribution in rat liver of polypeptides binding guanosine 5'-[gamma-[35S]thio]triphosphate [( 35S]GTP[S]) and seven antibodies against ras oncoproteins was evaluated. Multiple low-Mr (21,000-28,000) GTP-binding proteins were detected, but their relative distribution among the membrane fractions varied. A more specific compartmentation of polypeptides which bind antibodies generated against ras proteins was evident, with an Mr-28,000 polypeptide and a probable Mr-56,000 dimer, identified by six of the antibodies tested, being confined mainly to endosomes. An Mr-23,000 polypeptide was detected by some of the antibodies in all of the membrane fractions, but especially in the plasma membranes.
Ali
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National Institute for Medical Research, Mill Hill, London, U.K.
Evans
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WH
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000918:Antibody Specificity; D000941:Antigens / Q000276:immunology; D015153:Blotting, Western; D002462:Cell Membrane / Q000737:chemistry; D004705:Endocytosis; D019204:GTP-Binding Proteins / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism*; D007425:Intracellular Membranes / Q000737:chemistry; D008099:Liver / Q000737:chemistry / Q000648:ultrastructure*; D046911:Macromolecular Substances; D008970:Molecular Weight; D015689:Oncogene Protein p21(ras) / Q000276:immunology*; D051381:Rats; D011919:Rats, Inbred Strains; D013347:Subcellular Fractions / Q000737:chemistry*
D000906:Antibodies; D000941:Antigens; D046911:Macromolecular Substances; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins; D015689:Oncogene Protein p21(ras)