The sperm surface localization of the TRP-3/SPE-41 Ca^2 +-permeable channel depends on SPE-38 function in Caenorhabditis elegans

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• 作者：Gunasekaran Singaravelu^a ; ^{guna@waksman.rutgers.edu} ; Indrani Chatterjee^a ; Sina Rahimi^a ; Marina K. Druzhinina^a ; Lijun Kang^b ; X.Z. Shawn Xu^b ; Andrew Singson^a
• 关键词：Sperm ; Spermiogenesis ; Trafficking ; SPE-38 ; Calcium channel ; TRP-3/SPE-41
• 刊名：Developmental Biology
• 出版年：2012
• 期刊代码：167_00121606
• 类别：bio
• 出版时间：15 May, 2012
• 卷：365
• 期：2
• 页码：376-383
• 文件大小：603 K

摘要

Despite undergoing normal development and acquiring normal morphology and motility, mutations in spe-38 or trp-3/spe-41 cause identical phenotypes in Caenorhabditis elegans鈥攎utant sperm fail to fertilize oocytes despite direct contact. SPE-38 is a novel, four-pass transmembrane protein and TRP-3/SPE-41 is a Ca^2 +-permeable channel. Localization of both of these proteins is confined to the membranous organelles (MOs) in undifferentiated spermatids. In mature spermatozoa, SPE-38 is localized to the pseudopod and TRP-3/SPE-41 is localized to the whole plasma membrane. Here we show that the dynamic redistribution of TRP-3/SPE-41 from MOs to the plasma membrane is dependent on SPE-38. In spe-38 mutant spermatozoa, TRP-3/SPE-41 is trapped within the MOs and fails to reach the cell surface despite MO fusion with the plasma membrane. Split-ubiquitin yeast-two-hybrid analyses revealed that the cell surface localization of TRP-3/SPE-41 is likely regulated by SPE-38 through a direct protein-protein interaction mechanism. We have identified sequences that influence the physical interaction between SPE-38 and TRP-3/SPE-41, and show that these sequences in SPE-38 are required for fertility in transgenic animals. Despite the mislocalization of TRP-3/SPE-41 in spe-38 mutant spermatozoa, ionomycin or thapsigargin induced influx of Ca^2 + remains unperturbed. This work reveals a new paradigm for the regulated surface localization of a Ca^2 +-permeable channel.