The length of cargo-protein transmembrane segments drives secretory transport by facilitating cargo concentration in export domains
The length of cargo-protein transmembrane segments drives secretory transport by facilitating cargo concentration in export domains
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DOI：
10.1242/jcs.039339
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发表时间：
2009-06-01
影响因子：
4
通讯作者：
Hirschberg, Koret
中科院分区：
文献类型：
--
作者：
Dukhovny, Anna;Yaffe, Yakey;Hirschberg, Koret
分泌蛋白的细胞目的地是由它们的靶向基序与衣蛋白复合物的相互作用决定的。分泌蛋白的跨膜结构域（TMD）在它们的转运和靶向中也起着核心作用。然而，一个综合考虑TMD和靶向序列介导的转运的模型从未被提出。我们重点研究了两种荧光标记膜蛋白的分泌运输：水疱性口炎病毒gtso45 (VSVG)，这是一种热可逆突变的货物蛋白，以及高尔基驻留蛋白GalT-CFP。在活细胞中，采用定量方法分析了yfp标记的VSVG突变体在TMD上缺失1、3、5、7、8或9个氨基酸，以及在TMD上添加2或4个氨基酸的分泌运输动力学和货物浓度。TMD长度的变化影响了分泌运输动力学和内质网出口部位的货物集中程度，表明运输机械集中货物的能力取决于货物蛋白的TMD长度。
The cellular destination of secretory proteins is determined by interactions of their targeting motifs with coat-protein complexes. The transmembrane domain (TMD) of secretory proteins also plays a central role in their transport and targeting. However, a comprehensive model that considers both TMD- and targeting-sequence-mediated transport has never been advanced. We focused on the secretory transport of two fluorescently tagged membrane proteins: vesicular stomatitis virus G tsO45 (VSVG), which is a cargo protein that is a thermoreversible mutant, and the Golgi-resident protein GalT-CFP. A quantitative approach was applied to analyze, in living cells, secretory transport dynamics, as well as cargo concentration of YFP-tagged VSVG mutants with one, three, five, seven, eight or nine amino acids deleted from their TMD, as well as two or four amino acids added to their TMD. Changes in TMD length affected secretory transport dynamics and the extent of cargo concentration in the ER exit sites, demonstrating that the capacity of the transport machinery to concentrate cargo depends on the length of the TMD of the cargo protein.