The ubiquitous dermokine delta activates Rab5 function in the early endocytic pathway.
The ubiquitous dermokine delta activates Rab5 function in the early endocytic pathway.
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DOI：
10.1371/journal.pone.0017816
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发表时间：
2011-03-10
期刊：
影响因子：
3.7
通讯作者：
Jonca N
中科院分区：
文献类型：
--
作者：
Leclerc EA;Gazeilles L;Serre G;Guerrin M;Jonca N
最近发现的dermokine（Dmkn）基因的表达导致了四个家族的蛋白质与尚未未知的功能。分泌的α、β和γ同种型共享表皮限制性表达模式，而δ同种型是细胞内的并且普遍存在。为了深入了解Dmknδ的功能，我们进行了酵母双杂交筛选，并将小GTP酶Rab 5鉴定为Dmknδ的伴侣。已知Rab 5蛋白在早期内吞途径中调节膜对接和融合。GST pull-down分析证实Rab 5和Dmknδ之间存在直接相互作用。Dmknδ在HeLa细胞中的瞬时表达导致与内源性Rab 5和网格蛋白共定位的点状结构的形成，表明Dmknδ参与内吞作用的早期步骤。Dmknδ确实与转铁蛋白共定位在胞吞的早期阶段，但不调节其胞吞或再循环动力学。我们还表明，Dmknδ能够在体外结合Rab 5的非活性（GDP结合）和活性（GTP结合）形式，但在HeLa细胞中优先靶向GDP结合形式。有趣的是，Dmknδ表达挽救了Rab 5S 34 N介导的内体融合抑制。此外，Dmknδ通过促进GTP负载到小GTP酶上而引起Rab 5阳性囊泡的增大。总之，我们的数据表明，Dmknδ激活Rab 5功能，因此参与早期内体运输。
The expression of the recently identified dermokine (Dmkn) gene leads to four families of proteins with as yet unknown functions. The secreted α, β and γ isoforms share an epidermis-restricted expression pattern, whereas the δ isoform is intracellular and ubiquitous. To get an insight into Dmknδ function, we performed yeast two-hybrid screening and identified the small GTPases Rab5 as partners for Dmknδ. The Rab5 proteins are known to regulate membrane docking and fusion in the early endocytic pathway. GST pull-down assays confirmed the direct interaction between Rab5 and Dmknδ. Transient expression of Dmknδ in HeLa cells led to the formation of punctate structures colocalized with endogenous Rab5 and clathrin, indicating Dmknδ involvement in the early steps of endocytosis. Dmknδ indeed colocalized with transferrin at early stages of endocytosis, but did not modulate its endocytosis or recycling kinetics. We also showed that Dmknδ was able to bind both inactive (GDP-bound) and active (GTP-bound) forms of Rab5 in vitro but preferentially targeted GDP-bound form in HeLa cells. Interestingly, Dmknδ expression rescued the Rab5S34N-mediated inhibition of endosome fusion. Moreover, Dmknδ caused the enlargement of vesicles positive for Rab5 by promoting GTP loading onto the small GTPase. Together our data reveal that Dmknδ activates Rab5 function and thus is involved in the early endosomal trafficking.
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影响因子：
3.5
作者：
Moffatt, P;Salois, P;Lanctôt, C
通讯作者：
Lanctôt, C
DOI：
10.1083/jcb.149.4.901
发表时间：
2000-05-15
期刊：
The Journal of cell biology
影响因子：
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作者：
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作者：
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影响因子：
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作者：
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