Rab7 regulates transport from early to late endocytic compartments in Xenopus oocytes

Mukhopadhyay, Amitabha ; Funato, Kouichi ; Stahl, D. Philip (1997) Rab7 regulates transport from early to late endocytic compartments in Xenopus oocytes Journal of Biological Chemistry, 272 (20). pp. 13055-13059. ISSN 0021-9258

Full text not available from this repository.

Official URL: http://www.jbc.org/content/272/20/13055.abstract?s...

Related URL: http://dx.doi.org/10.1074/jbc.272.20.13055


Rab7 has been shown to localize to late endosomes and to mediate transport from early to late endosome/lysosome in mammalian cells and in yeast. We developed a novel assay to quantify transport from early to late endosomes using the Xenopusoocyte. Oocytes were pulsed with avidin after which the oocytes were incubated to allow avidin transport to a late compartment. The oocytes were then allowed to internalize biotin-horseradish peroxidase (HRP). The oocytes were then injected with test proteins and incubated further to allow transport of biotin-HRP from early endosomes to late endosomal/lysosomal compartments. Transport was quantified by assessing the formation of HRP-biotin-avidin complexes. Injection of Rab7:wild-type (WT) and Rab7:Q67L, a GTPase defective mutant, stimulated transport. Rab5:WT had no effect. Rab7:WT-stimulated transport was inhibited by nocodazole, suggesting a role for intact microtubules. Wortmannin, a phosphatidylinositol 3-kinase inhibitor, blocked Rab7:WT-stimulated transport, but Rab7:Q67L-stimulated transport was unaffected by the drug. Rab7:Q67L is constitutively activated and may not require phosphatidylinositol 3-kinase activity for activation. Rab7-stimulated transport requiresN-ethylmaleimide-sensitive factor (NSF) activity as transport was blocked by N-ethylmaleimide and ATPase defective NSF mutants. Our results indicate that sequentially acting endocytic Rab GTPases utilize similar factors although their modes of action may be different.

Item Type:Article
Source:Copyright of this article belongs to The American Society for Biochemistry and Molecular Biology.
ID Code:70212
Deposited On:21 Nov 2011 11:00
Last Modified:21 Nov 2011 11:00

Repository Staff Only: item control page