Wesp A, Hicke L, Palecek J, Lombardi R, Aust T, Munn A L, Riezman H
Biozentrum, University of Basel, Switzerland.
Mol Biol Cell. 1997 Nov;8(11):2291-306. doi: 10.1091/mbc.8.11.2291.
end4-1 was isolated as a temperature-sensitive endocytosis mutant. We cloned and sequenced END4 and found that it is identical to SLA2/MOP2. This gene is required for growth at high temperature, viability in the absence of Abp1p, polarization of the cortical actin cytoskeleton, and endocytosis. We used a mutational analysis of END4 to correlate in vivo functions with regions of End4p and we found that two regions of End4p participate in endocytosis but that the talin-like domain of End4p is dispensable. The N-terminal domain of End4p is required for growth at high temperature, endocytosis, and actin organization. A central coiled-coil domain of End4p is necessary for formation of a soluble sedimentable complex. Furthermore, this domain has an endocytic function that is redundant with the function(s) of ABP1 and SRV2. The endocytic function of Abp1p depends on its SH3 domain. In addition we have isolated a recessive negative allele of SRV2 that is defective for endocytosis. Combined biochemical, functional, and genetic analysis lead us to propose that End4p may mediate endocytosis through interaction with other actin-associated proteins, perhaps Rvs167p, a protein essential for endocytosis.
end4-1作为一种温度敏感型内吞作用突变体被分离出来。我们克隆并测序了END4，发现它与SLA2/MOP2相同。该基因对于高温下的生长、在没有Abp1p时的生存能力、皮质肌动蛋白细胞骨架的极化以及内吞作用是必需的。我们对END4进行了突变分析，以将体内功能与End4p的区域相关联，我们发现End4p的两个区域参与内吞作用，但End4p的类踝蛋白结构域是可有可无的。End4p的N端结构域对于高温下的生长、内吞作用和肌动蛋白组织是必需的。End4p的一个中央卷曲螺旋结构域对于形成可溶的可沉淀复合物是必要的。此外，该结构域具有与ABP1和SRV2的功能冗余的内吞作用功能。Abp1p的内吞作用功能取决于其SH3结构域。另外，我们分离出了一个SRV2的隐性负等位基因，其在内吞作用方面存在缺陷。综合的生化、功能和遗传分析使我们提出，End4p可能通过与其他肌动蛋白相关蛋白相互作用来介导内吞作用，也许是与Rvs167p相互作用，Rvs167p是一种内吞作用所必需的蛋白。
