A role for Rab5 activity in the biogenesis of endosomal and lysosomal compartments

Yuko Hirota, Toshio Kuronita, Hideaki Fujita, Yoshitaka Tanaka

研究成果: ジャーナルへの寄稿学術誌査読

37 被引用数 (Scopus)


Rab5 is a small GTPase that plays roles in the homotypic fusion of early endosomes and regulation of intracellular vesicle transport. We show here that expression of GFP-tagged GTPase-deficient form of Rab5b (Rab5bQ79L) in NRK cells results in the sequential formation of three morphologically and functionally distinct types of endosomes. Expression of GFP-Rab5bQ79L initially caused a homotypic fusion of early endosomes accompanying a redistribution of the TGN-resident cargo molecules, and subsequent fusion with late endosomes/lysosomes, leading to the formation of giant hybrid organelles with features of early endosomes and late endosomes/lysosomes. Surprisingly, the giant endosomes gradually fragmented and shrunk, leading to the accumulation of early endosome clusters and concurrent reformation of late endosomes/lysosomes, a process accelerated by treatment with a phosphatidylinositol-3-kinase (PI(3)K) inhibitor, wortmannin. We postulate that such sequential processes reflect the biogenesis and maintenance of late endosomes/lysosomes, presumably via direct fusion with early endosomes and subsequent fission from hybrid organelles. Thus, our findings suggest a regulatory role for Rab5 in not only the early endocytic pathway, but also the late endocytic pathway, of membrane trafficking in coordination with PI(3)K activity.

ジャーナルBiochemical and Biophysical Research Communications
出版ステータス出版済み - 12月 7 2007

!!!All Science Journal Classification (ASJC) codes

  • 生物理学
  • 生化学
  • 分子生物学
  • 細胞生物学


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