Li Wei, Walavalkar Ninad M, Buchwald William A, Teves Maria E, Zhang Ling, Liu Hong, Bilinovich Stephanie, Peterson Darrell L, Strauss Jerome F, Williams David C, Zhang Zhibing
Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, 23298.
Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599.
Sci Rep. 2016 Jan 4;6:18278. doi: 10.1038/srep18278.
The product of the meiosis-expressed gene 1 (MEIG1) is found in the cell bodies of spermatocytes and recruited to the manchette, a structure unique to elongating spermatids, by Parkin co-regulated gene (PACRG). This complex is essential for targeting cargo to the manchette during sperm flagellum assembly. Here we show that MEIG1 adopts a unique fold that provides a large surface for interacting with other proteins. We mutated 12 exposed and conserved amino acids and show that four of these mutations (W50A, K57E, F66A, Y68A) dramatically reduce binding to PACRG. These four amino acids form a contiguous hydrophobic patch on one end of the protein. Furthermore, each of these four mutations diminishes the ability of MEIG1 to stabilize PACRG when expressed in bacteria. Together these studies establish the unique structure and key interaction surface of MEIG1 and provide a framework to explore how MEIG1 recruits proteins to build the sperm tail.
减数分裂表达基因1（MEIG1）的产物存在于精母细胞的细胞体中，并由帕金共调控基因（PACRG）募集到精子延长小体，这是延长中的精子细胞特有的一种结构。这种复合体对于在精子鞭毛组装过程中将货物靶向运送到精子延长小体至关重要。在此我们表明，MEIG1呈现出一种独特的折叠结构，为与其他蛋白质相互作用提供了一个大的表面。我们对12个暴露且保守的氨基酸进行了突变，结果显示其中4个突变（W50A、K57E、F66A、Y68A）显著降低了与PACRG的结合。这4个氨基酸在该蛋白质的一端形成了一个连续的疏水斑块。此外，当在细菌中表达时，这4个突变中的每一个都削弱了MEIG1稳定PACRG的能力。这些研究共同确立了MEIG1的独特结构和关键相互作用表面，并提供了一个框架来探索MEIG1如何募集蛋白质以构建精子尾部。
