Small GTP-Binding Proteins on Rat Liver Lysosomal Membranes

[摘要] References(39)Cited-By(5)GTP-binding proteins have been identified on the membranes of highly purified dextran-filled lysosomes (dextranosomes) and Triton-filled lysosomes (tritosomes) obtained from rat liver. Autoradiography of blots of lysosomal membrane proteins incubated with [α-32P]GTP revealed the presence of several specific GTP-binding proteins with a relative molecular mass (Mr) predominantly in the range of 26-30 kDa. These GTP-binding proteins migrated slower in polyacrylamide gels than purified c-Ha-ras protein expressed in E. coli, whose apparent Mr was 23 kDain the same blot. The relative contents of GTP-binding proteins in lysosomal membranes were comparable or greater than that of plasma membranes and of microsomes. Chemical extraction showed that lysosomal GTP-binding proteins were more tightly associated with the membranes than with microsomal GTP-binding proteins. The possible involvement of lysosomal GTP-binding proteins in cellular functions including vacuolar (lysosomal) acidification and organellar dynamics are discussed.

[学科分类] 分子生物学，细胞生物学和基因

[关键词] GTP-binding protein;lysosome;ras