Dynamic changes in the spatiotemporal localization of Rab21 in live RAW264 cells during macropinocytosis.
Dynamic changes in the spatiotemporal localization of Rab21 in live RAW264 cells during macropinocytosis.
复制标题
DOI：
10.1371/journal.pone.0006689
复制
发表时间：
2009-08-20
期刊：
影响因子：
3.7
通讯作者：
Araki N
中科院分区：
文献类型：
--
作者：
Egami Y;Araki N
Rab21是rabgtpase家族的一员，已知参与细胞膜运输，但其在巨噬细胞增多症中的含义尚不清楚。我们通过荧光蛋白融合Rab21的活细胞成像分析Rab21在m - csf刺激的RAW264巨噬细胞中的时空定位。结果表明，野生型Rab21与巨肽体有短暂的关联。在PI(4,5)P2和PI(3,4,5)P3水平降低后，Rab21被招募到大蛋白酶体中。虽然Rab21在很大程度上与Rab5共定位，但Rab21对大酶体的招募比Rab5晚一分钟，比Rab7早一分钟。然后，Rab21在Lamp1积累之前从大蛋白酶体中分离出来，Lamp1是一种晚期内体/溶酶体标记物。我们对Rab21突变体的分析显示，与gtp结合的突变体Rab21- q78l与野生型Rab21相似，被招募到大酶体中。然而，GTP结合的突变体Rab21- t33n没有定位在形成的大脂小体上，这表明GTP与Rab21的结合是Rab21正确募集到大脂小体上所必需的。然而，Rab21突变均未显著影响大肌醇体的形成率。这些数据表明Rab21是巨量红细胞增多症早期和中期的短暂成分，可能在巨量红细胞增多症与溶酶体室室融合之前发挥作用。
Rab21, a member of the Rab GTPase family, is known to be involved in membrane trafficking, but its implication in macropinocytosis is unclear. We analyzed the spatiotemporal localization of Rab21 in M-CSF-stimulated RAW264 macrophages by the live-cell imaging of fluorescent protein-fused Rab21. It was demonstrated that wild-type Rab21 was transiently associated with macropinosomes. Rab21 was recruited to the macropinosomes after a decrease in PI(4,5)P2 and PI(3,4,5)P3 levels. Although Rab21 was largely colocalized with Rab5, the recruitment of Rab21 to the macropinosomes lagged a minute behind that of Rab5, and preceded that of Rab7. Then, Rab21 was dissociated from the macropinosomes prior to the accumulation of Lamp1, a late endosomal/lysosomal marker. Our analysis of Rab21 mutants revealed that the GTP-bound mutant, Rab21-Q78L, was recruited to the macropinosomes, similarly to wild-type Rab21. However, the GDP-bound mutant, Rab21-T33N, did not localize on the formed macropinosomes, suggesting that the binding of GTP to Rab21 is required for the proper recruitment of Rab21 onto the macropinosomes. However, neither mutation of Rab21 significantly affected the rate of macropinosome formation. These data indicate that Rab21 is a transient component of early and intermediate stages of macropinocytosis, and probably functions in macropinosome maturation before fusing with lysosomal compartments.
登录
查看更多内容
影响因子：
4.8
作者：
Donaldson, Julie G.;Porat-Shliom, Natalie;Cohen, Lee Ann
通讯作者：
Cohen, Lee Ann
影响因子：
15.3
作者：
RACOOSIN, EL;SWANSON, JA
通讯作者：
SWANSON, JA
影响因子：
5.3
作者：
Jones AT
通讯作者：
Jones AT
DOI：
10.1083/jcb.134.4.935
发表时间：
1996-08
期刊：
The Journal of cell biology
影响因子：
--
作者：
Radhakrishna H;Klausner RD;Donaldson JG
通讯作者：
Donaldson JG
影响因子：
3.3
作者：
Porat-Shliom, Natalie;Kloog, Yoel;Donaldson, Julie G.
通讯作者：
Donaldson, Julie G.