Deletion mutants of AP-1 adaptin subunits display distinct phenotypes in fission yeast
Deletion mutants of AP-1 adaptin subunits display distinct phenotypes in fission yeast
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DOI：
10.1111/j.1365-2443.2009.01327.x
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发表时间：
2009-08-01
期刊：
影响因子：
2.1
通讯作者：
Kuno, Takayoshi
中科院分区：
文献类型：
--
作者：
Ma, Yan;Takeuchi, Mai;Kuno, Takayoshi
衔接蛋白是异源四聚体（β/μ/γ/σ）衔接蛋白（AP）复合物的亚基，其参与网格蛋白介导的膜运输。在这里，我们表明，在粟酒裂殖酵母中，AP-1复合物[Apl 2（β），Apl 4（γ），Apm 1（mu）和Aps 1（sigma）]的每个单独亚基的缺失菌株引起对温度或药物的生长敏感性的不同表型。我们还表明，三角洲apm 1和三角洲apl 2突变体显示类似的，但更严重的表型比三角洲aps 1或三角洲apl 4突变体。此外，Delta apl 2 Delta aps 1和Delta apl 2 Delta apl 4双突变体显示合成生长缺陷，而Delta aps 1 Delta apl 4和Delta apl 2 Delta apm 1双突变体没有。在下拉测定中，Apm 1甚至在Aps 1和Apl 4不存在的情况下结合Apl 2，并且Apl 4甚至在Apm 1和Apl 2不存在的情况下结合Aps 1。一致地，任何亚基的缺失通常导致异源四聚体复合物从内体解离，尽管一些亚基弱地定位于内体。此外，单个亚基的缺失导致v-SNARE小突触泡蛋白Syb 1的内体积累相似。总之，结果表明，这四个亚基都是必不可少的异源四聚体复合物的形成和AP-1的功能，从内体出口运输。
Adaptins are subunits of the heterotetrameric (beta/mu/gamma/sigma) adaptor protein (AP) complexes that are involved in clathrin-mediated membrane trafficking. Here, we show that in Schizosaccharomyces pombe the deletion strains of each individual subunit of the AP-1 complex [Apl2 (beta), Apl4 (gamma), Apm1 (mu) and Aps1 (sigma)] caused distinct phenotypes on growth sensitivity to temperature or drugs. We also show that the Delta apm1 and Delta apl2 mutants displayed similar but more severe phenotypes than those of Delta aps1 or Delta apl4 mutants. Furthermore, the Delta apl2 Delta aps1 and Delta apl2 Delta apl4 double mutants displayed synthetic growth defects, whereas the Delta aps1 Delta apl4 and Delta apl2 Delta apm1 double mutants did not. In pull-down assay, Apm1 binds Apl2 even in the absence of Aps1 and Apl4, and Apl4 binds Aps1 even in the absence of Apm1 and Apl2. Consistently, the deletion of any subunit generally caused the disassociation of the heterotetrameric complex from endosomes, although some subunits weakly localized to endosomes. In addition, the deletion of individual subunits caused similar endosomal accumulation of v-SNARE synaptobrevin Syb1. Altogether, results suggest that the four subunits are all essential for the heterotetrameric complex formation and for the AP-1 function in exit transport from endosomes.