The ARF-like GTPases Arl1p and Arl3p act in a pathway that interacts with vesicle-tethering factors at the Golgi apparatus
The ARF-like GTPases Arl1p and Arl3p act in a pathway that interacts with vesicle-tethering factors at the Golgi apparatus
复制标题
DOI：
10.1016/s0960-9822(03)00091-5
复制
发表时间：
2003-03-04
期刊：
影响因子：
9.2
通讯作者：
Munro, S
中科院分区：
文献类型：
--
作者：
Panic, B;Whyte, JRC;Munro, S
ARL 是 GTP 酶的一个多样化家族，与 ADP 核糖基化因子 (ARF) 相关，但对其功能知之甚少。人类中至少有十种 ARL，其中两种在酿酒酵母中具有同源物（ARL1/Arl1p 和 ARFRP1/Arl3p）。 ARFRP1 的功能尚不清楚，但最近发现哺乳动物 ARL1 与许多效应子相互作用，包括存在于高尔基体定位的长卷曲螺旋蛋白家族中的 GRIP 结构域 [1]。我们发现，在酵母中，Imh1p（唯一的酵母 GRIP 结构域蛋白）的细胞内靶向依赖于 Arl1p 和 Arl3p，但不依赖于 ARF 蛋白。 Imh1p GRIP 结构域的重组形式以 GTP 依赖性方式与 Arl1p 结合，但不与 Arl3p 结合。酵母还含有 SCOCO 的亲戚，一种被认为可以结合人类 ARL1 的蛋白质，但这种酵母蛋白质 Slo1p 在体外似乎结合 Arl3p 而不是 Arl1p。然而，Imh1p 并不是 Arl1p 的唯一效应器，因为固定化 Arl1p:GTP 的胞质溶胶的亲和层析揭示了与 GARP/VFT 复合物的相互作用，该复合物被认为在将囊泡束缚到高尔基体上发挥作用 [2,3]。最后，我们发现 Arl3p 是体内 Arl1p 靶向所必需的，这解释了其对 Imh1p 正态分布的要求。
The ARLs are a diverse family of GTPases that are related to ADP-ribosylation factors (ARFs), but whose function is poorly understood. There are at least ten ARLs in humans, two of which have homologs in the yeast Saccharomyces cerevisiae (ARL1/Arl1p and ARFRP1/Arl3p). The function of ARFRP1 is unknown , but mammalian ARL1 has recently been found to interact with a number of effectors including the GRIP domain that is present in a family of Golgi-localized long coiled-coil proteins [1]. We find that in yeast, the intracellular targeting of Imh1p, the only yeast GRIP domain protein, is dependent on both Arl1p and Arl3p, but not on the ARF proteins. A recombinant form of the Imh1p GRIP domain binds to Arl1p in a GTP-dependent manner, but not to Arl3p. Yeast also contain a relative of SCOCO, a protein proposed to bind human ARL1, but this yeast protein, Slo1p, appears to bind Arl3p rather than Arl1p in vitro. However, Imh1p is not the sole effector of Arl1p since affinity chromatography of cytosol with immobilized Arl1p:GTP revealed an interaction with the GARP/VFT complex that is thought to act in the tethering of vesicles to the Golgi apparatus [2,3]. Finally, we find that Arl3p is required in vivo for the targeting of Arl1p, explaining its requirement for the normal distribution of Imh1p.