文章基本信息

标题：Functional and structural characterization of a dense core secretory granule sorting domain from the PC1/3 protease
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作者：Jimmy D. Dikeakos ; Paola Di Lello ; Marie-Josée Lacombe 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2009
卷号：106
期号：18
页码：7408-7413
DOI：10.1073/pnas.0809576106
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Several peptide hormones are initially synthesized as inactive precursors. It is only on entry of these prohormones and their processing proteases into dense core secretory granules (DCSGs) that the precursors are cleaved to generate their active forms. Prohormone convertase (PC)1/3 is a processing protease that is targeted to DCSGs. The signal for targeting PC1/3 to DCSGs resides in its carboxy-terminal tail (PC1/3617-753), where 3 regions (PC1/3617-625, PC1/3665-682, and PC1/3711-753) are known to aid in sorting and membrane association. In this article, we have determined a high-resolution structure of the extreme carboxy-terminal sorting domain, PC1/3711-753 in micelles by NMR spectroscopy. PC1/3711-753 contains 2 alpha helices located between residues 722-728 and 738-750. Functional assays demonstrate that the second helix (PC1/3738-750) is necessary and sufficient to target a constitutively secreted protein to granules, and that L745 anchors a hydrophobic patch that is critical for sorting. Also, we demonstrate that calcium binding by the second helix of PC1/3711-753 promotes aggregation of the domain via the hydrophobic patch centered on L745. These results provide a structure-function analysis of a DCSG-sorting domain, and reveal the importance of a hydrophobic patch and calcium binding in controlling the sorting of proteins containing alpha helices to DCSGs.
关键词：NMR ; prohormone convertases