Mechanisms underlying the inhibition of murine sperm capacitation by the seminal protein, SPINKL
Mechanisms underlying the inhibition of murine sperm capacitation by the seminal protein, SPINKL
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DOI：
10.1002/jcb.24428
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发表时间：
2013-04-01
影响因子：
4
通讯作者：
Li, Sheng-Hsiang
中科院分区：
文献类型：
--
作者：
Tseng, Huan-Chin;Lee, Robert Kuo-Kuang;Li, Sheng-Hsiang
SPINKL是一种最初在小鼠精囊分泌物中发现的丝氨酸蛋白酶抑制剂kazal型样蛋白，具有结构保守的kazal型丝氨酸蛋白酶抑制剂家族的6 -半胱氨酸残基。但对丝氨酸蛋白酶无抑制作用。此前，在体外实验中发现它具有抑制小鼠精子获能的能力。在此，我们研究了SPINKL对精子获能抑制作用的机制。采用牛血清白蛋白（BSA）、甲基- β -环糊精（MBCD）和二丁基环AMP (dbcAMP) 3种体外获能增强剂，偶联3-异丁基-1-甲基黄嘌呤（IBMX），研究SPINKL对获能信号通路的影响。SPINKL通过阻断3个上游信号，即胆固醇从精子质膜流出、细胞外钙离子流入精子和细胞内cAMP增加，抑制了BSA-和mbcd诱导的精子获能。此外，SPINKL还抑制了下游信号转导，因为它抑制了dbcAMP/IBMX和n6 -苯基cAMP （6- ph -cAMP）激活的cAMP依赖蛋白激酶相关蛋白酪氨酸磷酸化。这种抑制可能是由SRC酪氨酸激酶活性的衰减介导的。此外，SPINKL不能逆转精子被获能增强剂或在试管内获能后的获能。与精子结合的SPINKL在子宫中存在，但在精子通过女性生殖道的过程中从输卵管中的精子中消失。因此，SPINKL可能作为子宫内的失能因子，防止精子过早获能及随后的顶体反应，从而保持精子的受精能力。j .细胞。中国生物医学工程学报，2014,31(2):481 - 481。(c) 2012 Wiley期刊有限公司
SPINKL, a serine protease inhibitor kazal-type-like protein initially found in mouse seminal vesicle secretions, possesses structurally conserved six-cysteine residues of the kazal-type serine protease inhibitor family. However, it has no inhibitory activity against serine proteases. Previously, it was found to have the ability to suppress murine sperm capacitation in vitro. Herein, we investigated the mechanisms underlying the suppressive effect of SPINKL on sperm capacitation. Three in vitro capacitation-enhancing agents, including bovine serum albumin (BSA), methyl-beta-cyclodextrin (MBCD), and dibutyryl cyclic AMP (dbcAMP), coupled with 3-isobutyl-1-methylxanthine (IBMX), were used to evaluate the influence of SPINKL on capacitation signaling. Preincubation of sperm with SPINKL suppressed BSA- and MBCD-induced sperm capacitation by blocking three upstream signals of capacitation that is the cholesterol efflux from sperm plasma membranes, extracellular calcium ion influx into sperm, and increases in intracellular cAMP. Moreover, SPINKL also inhibited downstream signal transduction of capacitation since it suppressed dbcAMP/IBMX and N6-phenyl cAMP (6-Phe-cAMP)-activated cAMP-dependent protein kinase-associated protein tyrosine phosphorylation. Such inhibition is probably mediated by attenuation of SRC tyrosine kinase activity. Furthermore, SPINKL could not reverse capacitation once sperm had been capacitated by capacitation-enhancing agents or capacitated in vivo in the oviduct. SPINKL bound to sperm existed in the uterus but had disappeared from sperm in the oviduct during the sperm's transit through the female reproductive tract. Therefore, SPINKL may serve as an uncapacitation factor in the uterus to prevent sperm from precocious capacitation and the subsequent acrosome reaction and thus preserve the fertilization ability of sperm. J. Cell. Biochem. 114: 888898, 2013. (c) 2012 Wiley Periodicals, Inc.