MARCH ubiquitin ligases alter the itinerary of clathrin-independent cargo from recycling to degradation.
MARCH ubiquitin ligases alter the itinerary of clathrin-independent cargo from recycling to degradation.
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DOI：
10.1091/mbc.e10-11-0874
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发表时间：
2011-09
影响因子：
3.3
通讯作者：
Donaldson JG
中科院分区：
文献类型：
--
作者：
Eyster CA;Cole NB;Petersen S;Viswanathan K;Früh K;Donaldson JG
MARCH蛋白家族是下调表面膜蛋白的膜相关E3泛素连接酶。MARCH 8在细胞中的表达导致表面CD 98和CD 44货物蛋白的泛素化和下调，这些蛋白通过网格蛋白非依赖性内吞作用进入细胞，并且通常被路由到再循环，而不是降解。内吞作用后，内化的质膜蛋白可以再循环回到细胞表面或运输到晚期内体/溶酶体进行降解。在这里，我们报告了通过网格蛋白非依赖性内吞作用（CIE）进入细胞的多种蛋白质的运输，并确定一组蛋白质主要在再循环小管中发现的CD 44、CD 98和CD 147在很大程度上不能到达HeLa细胞中的晚期内体，而其他CIE货物蛋白，包括主要组织相容性复合物I类蛋白（MHCI），除了再循环小管之外，还被运输到早期内体抗原1（EEA 1）和晚期内体区室。膜相关RING-CH 8（MARCH 8）E3泛素连接酶的表达完全转移了CD 44和CD 98蛋白从再循环小管到EEA 1隔室和晚期内体的运输，导致表面水平降低。受MARCH表达影响的货物，包括CD 44，CD 98和MHCI，仍然通过CIE进入细胞，表明泛素化货物的路由发生在内吞作用后。MARCH 8表达导致CD 98的直接泛素化和CD 98向晚期内体/溶酶体的路由。
The MARCH family of proteins are membrane-associated E3 ubiquitin ligases that down-regulate surface membrane proteins. Expression of MARCH8 in cells causes the ubiquitination and down-regulation of surface CD98 and CD44—cargo proteins that enter cells by clathrin-independent endocytosis and are usually routed to recycling, not degradation. Following endocytosis, internalized plasma membrane proteins can be recycled back to the cell surface or trafficked to late endosomes/lysosomes for degradation. Here we report on the trafficking of multiple proteins that enter cells by clathrin-independent endocytosis (CIE) and determine that a set of proteins (CD44, CD98, and CD147) found primarily in recycling tubules largely failed to reach late endosomes in HeLa cells, whereas other CIE cargo proteins, including major histocompatibility complex class I protein (MHCI), trafficked to both early endosome antigen 1 (EEA1) and late endosomal compartments in addition to recycling tubules. Expression of the membrane-associated RING-CH 8 (MARCH8) E3 ubiquitin ligase completely shifted the trafficking of CD44 and CD98 proteins away from recycling tubules to EEA1 compartments and late endosomes, resulting in reduced surface levels. Cargo affected by MARCH expression, including CD44, CD98, and MHCI, still entered cells by CIE, suggesting that the routing of ubiquitinated cargo occurs after endocytosis. MARCH8 expression led to direct ubiquitination of CD98 and routing of CD98 to late endosomes/lysosomes.