Endocytic crosstalk: cavins, caveolins, and caveolae regulate clathrin-independent endocytosis.
Endocytic crosstalk: cavins, caveolins, and caveolae regulate clathrin-independent endocytosis.
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DOI：
10.1371/journal.pbio.1001832
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发表时间：
2014-04
期刊：
影响因子：
9.8
通讯作者：
Parton RG
中科院分区：
文献类型：
--
作者：
Chaudhary N;Gomez GA;Howes MT;Lo HP;McMahon KA;Rae JA;Schieber NL;Hill MM;Gaus K;Yap AS;Parton RG
小窝蛋白和小窝负调控第二个不依赖于笼蛋白的内吞CLIC/GEEC途径；小窝蛋白-1影响RAFT相关CLIC货物的膜扩散特性，而小窝蛋白-1的支架结构域是内吞抑制所必需的且充分的。一些研究表明，不同的胞内蛋白非依赖性内吞途径之间存在串扰。然而，这些相互作用的分子机制和功能相关性尚不清楚。Caveolins和Cavins是小窝的重要组成部分，小窝是一种特殊的微域，也构成内吞途径。在这里，我们展示了特定的空泡蛋白是独立作用于非细胞吞噬蛋白的负调控因子。Cavin-1和Cavin-3，而不是Cavin-2或Cavin-4，是Cavin-2或Cavin-4的有效抑制剂，可以抑制Cathrin非依赖载体/GPI-AP富含早期内膜室(CLIC/GEEC)的内吞途径，该过程不依赖于小窝的形成。CAV1和CAV3还可抑制CLIC/GEEC途径的过度表达。定量电子显微镜分析发现，空泡蛋白的表达导致早期CLIC/GEEC携带者的形成减少。此外，在CAV1/Cavin-1缺失或Cavin-1和Cavin-3表达降低的细胞中，CLIC/GEEC通路上调。小窝蛋白的抑制作用可以通过分离的小窝蛋白支架结构域来模拟，并与脂类微域成分的扰动扩散有关，如光漂白后荧光恢复(FRAP)研究所揭示的那样。在没有小窝(和小窝)的情况下，CAV1本身优先通过CLIC/GEEC途径内吞，但该途径失去了极化和分选属性，从而影响了迁移细胞和成年肌肉组织的膜动力学和内吞极化。我们还发现，非空泡Cavin-1可以作为CLIC/GEEC途径的关键调节因子CDc42的调节器。这项工作提供了新的洞察力，通过特定的空泡蛋白调节非空泡蛋白非依赖性内吞作用，说明了这些通路之间的多个水平的串扰。我们首次发现了特定的Cavins在调节CLIC/GEEC途径中的作用，为研究这一途径提供了一个新的工具，鉴定了Cavins的非小窝依赖功能，并提出了一种新的小窝蛋白抑制CLIC/GEEC途径的机制。内吞作用是细胞从环境中摄取分子的过程。哺乳动物细胞中存在几种内吞途径。虽然最了解的内吞途径是使用胞苷，但近年来我们对胞苷非依赖的胞内途径的了解有了很大的提高。在这里，我们描述了质膜上存在的小凹、烧瓶状专门微域和第二个不依赖于笼蛋白的途径，即CLIC/GEEC CDC42调节的内吞途径之间的串扰。这些途径被隔离在迁移细胞中，小凹位于后方，CLIC/GEEC内吞作用位于前缘。在这里，我们发现特定的小窝蛋白，小窝蛋白和小窝蛋白，也可以负向调节CLIC/GEEC途径。借助于包括定量电子显微镜分析和实时活细胞成像在内的几种技术，我们证明空泡蛋白的表达影响早期载体的形成，导致细胞脂质变化，并改变CLIC/GEEC途径的关键调节因子CDC42的活性。空泡蛋白在CLIC/GEEC途径上丢失的功能后果包括抑制极化细胞迁移和增加组织外植体的内吞作用。
Caveolar proteins and caveolae negatively regulate a second clathrin-independent endocytic CLIC/GEEC pathway; caveolin-1 affects membrane diffusion properties of raft-associated CLIC cargo, and the scaffolding domain of caveolin-1 is required and sufficient for endocytic inhibition. Several studies have suggested crosstalk between different clathrin-independent endocytic pathways. However, the molecular mechanisms and functional relevance of these interactions are unclear. Caveolins and cavins are crucial components of caveolae, specialized microdomains that also constitute an endocytic route. Here we show that specific caveolar proteins are independently acting negative regulators of clathrin-independent endocytosis. Cavin-1 and Cavin-3, but not Cavin-2 or Cavin-4, are potent inhibitors of the clathrin-independent carriers/GPI-AP enriched early endosomal compartment (CLIC/GEEC) endocytic pathway, in a process independent of caveola formation. Caveolin-1 (CAV1) and CAV3 also inhibit the CLIC/GEEC pathway upon over-expression. Expression of caveolar protein leads to reduction in formation of early CLIC/GEEC carriers, as detected by quantitative electron microscopy analysis. Furthermore, the CLIC/GEEC pathway is upregulated in cells lacking CAV1/Cavin-1 or with reduced expression of Cavin-1 and Cavin-3. Inhibition by caveolins can be mimicked by the isolated caveolin scaffolding domain and is associated with perturbed diffusion of lipid microdomain components, as revealed by fluorescence recovery after photobleaching (FRAP) studies. In the absence of cavins (and caveolae) CAV1 is itself endocytosed preferentially through the CLIC/GEEC pathway, but the pathway loses polarization and sorting attributes with consequences for membrane dynamics and endocytic polarization in migrating cells and adult muscle tissue. We also found that noncaveolar Cavin-1 can act as a modulator for the activity of the key regulator of the CLIC/GEEC pathway, Cdc42. This work provides new insights into the regulation of noncaveolar clathrin-independent endocytosis by specific caveolar proteins, illustrating multiple levels of crosstalk between these pathways. We show for the first time a role for specific cavins in regulating the CLIC/GEEC pathway, provide a new tool to study this pathway, identify caveola-independent functions of the cavins and propose a novel mechanism for inhibition of the CLIC/GEEC pathway by caveolin. Endocytosis is the process that allows cells to take up molecules from the environment. Several endocytic pathways exist in mammalian cells. While the best understood endocytic pathway uses clathrin, recent years have seen a great increase in our understanding of clathrin-independent endocytic pathways. Here we characterize the crosstalk between caveolae, flask-shaped specialized microdomains present at the plasma membrane, and a second clathrin-independent pathway, the CLIC/GEEC Cdc42-regulated endocytic pathway. These pathways are segregated in migrating cells with caveolae at the rear and CLIC/GEEC endocytosis at the leading edge. Here we find that specific caveolar proteins, caveolins and cavins, can also negatively regulate the CLIC/GEEC pathway. With the help of several techniques, including quantitative electron microscopy analysis and real-time live-cell imaging, we demonstrate that expression of caveolar proteins affects early carrier formation, causes cellular lipid changes, and changes the activity of the key regulator of the CLIC/GEEC pathway, Cdc42. The functional consequences of loss of caveolar proteins on the CLIC/GEEC pathway included inhibition of polarized cell migration and increased endocytosis in tissue explants.
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影响因子：
3.7
作者：
Hill MM;Daud NH;Aung CS;Loo D;Martin S;Murphy S;Black DM;Barry R;Simpson F;Liu L;Pilch PF;Hancock JF;Parat MO;Parton RG
通讯作者：
Parton RG
影响因子：
4.8
作者：
Donaldson, Julie G.;Porat-Shliom, Natalie;Cohen, Lee Ann
通讯作者：
Cohen, Lee Ann
DOI：
10.1083/jcb.201307055
发表时间：
2014-03-03
期刊：
The Journal of cell biology
影响因子：
--
作者：
Ariotti N;Fernández-Rojo MA;Zhou Y;Hill MM;Rodkey TL;Inder KL;Tanner LB;Wenk MR;Hancock JF;Parton RG
通讯作者：
Parton RG
DOI：
10.1083/jcb.200903053
发表时间：
2009-06-29
期刊：
The Journal of cell biology
影响因子：
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作者：
Bastiani M;Liu L;Hill MM;Jedrychowski MP;Nixon SJ;Lo HP;Abankwa D;Luetterforst R;Fernandez-Rojo M;Breen MR;Gygi SP;Vinten J;Walser PJ;North KN;Hancock JF;Pilch PF;Parton RG
通讯作者：
Parton RG
DOI：
10.1083/jcb.201003086
发表时间：
2010-11-01
期刊：
The Journal of cell biology
影响因子：
--
作者：
Hayer A;Stoeber M;Ritz D;Engel S;Meyer HH;Helenius A
通讯作者：
Helenius A