GTP-binding mutants of rab1 and rab2 are potent inhibitors of vesicular transport from the endoplasmic reticulum to the Golgi complex.

摘要: We have examined the role of ras-related rab proteins in transport from ER to Golgi complex vivo using a vaccinia recombinant T7 RNA polymerase virus express site-directed mutants. These mutations are within highly conserved domains involved guanine nucleotide binding and hydrolysis found ras all members superfamily. Substitutions GTP-binding rab1a rab1b (equivalent 17N 116I mutants) resulted which were potent trans dominant inhibitors vesicular stomatitis glycoprotein (VSV-G protein) between cis complex. Immunofluorescence analysis indicated that expression rab1b121I prevented delivery VSV-G protein stack, accumulation pre-Golgi punctate structures. Mutants exchange or rab2 also strong inhibitors. Analogous rab3a, rab5, rab6, H-ras did not inhibit processing complex, sialic acid containing form diagnostic compartment. suggest at least three family (rab1a, rab1b, rab2) use GTP regulate components machinery vesicle traffic early compartments secretory pathway.