Role of Rab9 GTPase in facilitating receptor recruitment by TIP47
Role of Rab9 GTPase in facilitating receptor recruitment by TIP47
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DOI：
10.1126/science.1056791
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发表时间：
2001-05-18
期刊：
影响因子：
56.9
通讯作者：
Pfeffer, SR
中科院分区：
文献类型：
--
作者：
Carroll, KS;Hanna, J;Pfeffer, SR
甘露糖 - 6 - 磷酸受体（MPRs）将溶酶体水解酶从高尔基体运输到内体，然后再返回高尔基体复合物。TIP47识别MPRs的胞质结构域，并且是内体到高尔基体运输所必需的。在此我们表明，TIP47在其活性的、结合GTP的构象下也直接与Rab9鸟苷三磷酸酶（GTP酶）结合。此外，Rab9增加了TIP47对其货物的亲和力。一个有功能的Rab9结合位点是TIP47在体内刺激MPR运输所必需的。因此，一种胞质货物选择装置可能被选择性地招募到特定的细胞器上，并且囊泡出芽可能与活性Rab GTP酶的存在相关联。
Mannose 6-phosphate receptors (MPRs) deliver lysosomal hydrolases from the Golgi to endosomes and then return to the Golgi complex. TIP47 recognizes the cytoplasmic domains of MPRs and is required for endosome-to-Golgi transport. Here we show that TIP47 also bound directly to the Rab9 guanosine triphosphatase (GTPase) in its active, GTP-bound conformation. Moreover, Rab9 increased the affinity of TIP47 for its cargo. A functional Rab9 binding site was required for TIP47 stimulation of MPR transport in vivo. Thus, a cytosolic cargo selection device may be selectively recruited onto a specific organelle, and vesicle budding might be coupled to the presence of an active Rab GTPase.