Caveolin-1 activates Rab5 and enhances endocytosis through direct interaction

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• 作者：Makoto Hagiwara ; Yukiya Shirai ; Ryosuke Nomura ; Mikio Sasaki ; Ken-Ichi Kobayashi ; Tadahiro Tadokoro ; Yuji Yamamoto
• 关键词：b5 ; Caveolae ; Endocytosis
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2009
• 出版时间：2 January 2009
• 年：2009
• 卷：378
• 期：1
• 页码：73-78
• 全文大小：755 K

文摘

Caveolin-1, a constitutive protein of the caveolae, is implicated in processes of vesicular transport during caveolae-mediated endocytosis. However, the molecular mechanisms of caveolae-mediated endocytosis are not yet clearly defined. Here, we show the physiological role of the Rab5–caveolin-1 interaction during caveolae-mediated endocytosis. Rab5 was found in caveolae-enriched fractions and Rab5 directly bound to caveolin-1. Furthermore, binding sites of Rab5 to caveolin-1 were identified in the scaffold (SD), transmembrane (TM), and C-terminus (CC) domains, and the Rab5 binding domain of caveolin-1 was required for CTXB uptake. Subsequently, we performed a GST-R5BD pull-down assay to determine whether the Rab5 binding domain of caveolin-1 is involved in Rab5 activity or not. The results showed that overexpression of the Rab5 binding domain of caveolin-1 increase the amount of Rab5-GTP in Cos-1 cells. These findings imply that caveolin-1 controls the Rab5 activity during the caveolae-mediated endocytosis.