SLO3 auxiliary subunit LRRC52 controls gating of sperm KSPER currents and is critical for normal fertility
SLO3 auxiliary subunit LRRC52 controls gating of sperm KSPER currents and is critical for normal fertility
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SLO3 辅助亚基 LRRC52 控制精子 KSPER 电流的门控，对于正常生育能力至关重要
DOI：
10.1073/pnas.1423869112
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发表时间：
2015-02-24
影响因子：
11.1
通讯作者：
Lingle, Christopher J.
中科院分区：
文献类型：
--
作者：
Zeng, Xu-Hui;Yang, Chengtao;Lingle, Christopher J.
哺乳动物精子的生育力取决于两个精子特异性离子通道的协同激活，即碱化激活的Ca 2+渗透性精子通道和精子pH调节的K+电流（KSPER）通道;两者都是生育力所必需的。在小鼠中，KSPER通道被认为涉及由slo 3基因亚基和富含亮氨酸重复序列的蛋白52（LRRC 52）辅助亚基编码的成孔离子通道蛋白和亚基的复合物。我们现在表明，KO的LRRC 52导致严重受损的生育能力和转移KSPER电流激活远离生理范围。此外，利用不同的平均KSPER电流量的基因型，我们表明，精子生育力表现出一个陡峭的依赖于可用的KSPER电流的量。结果表明，LRRC 52是精子KSPER功能的关键决定因素，对支持正常生育力至关重要。进入雌性生殖道后，哺乳动物精子经历一个成熟过程，称为获能，导致卵子受精。与获能相关的是对Ca 2+和K+的膜电导增加，导致细胞溶质Ca 2+升高，这对于超活化游泳运动的激活至关重要。在小鼠中，Ca 2+电导（碱化激活的Ca 2+渗透精子通道，CATSPER）来自CATSPER亚基的集合，而K+电导（精子pH调节的K+电流，KSPER）来自由slo 3基因（SLO 3）亚基编码的成孔离子通道亚基。在小鼠中，CATSPER和KSPER都被细胞溶质碱化激活，CATSPER和KSPER的协同激活可能是各种哺乳动物物种中与获能相关的Ca 2+和K+电导增加的共同方面。异源表达的小鼠SLO 3通道的特性不同于天然小鼠KSPER电流。最近，在小鼠精子中发现了一种潜在的KSPER辅助亚基，即富含亮氨酸重复序列的蛋白52（LRRC 52），并显示其改变SLO 3的门控，使其更等效于天然KSPER。在这里，我们表明LRRC 52的遗传KO导致小鼠生育力严重受损。在缺乏LRRC 52的精子中激活KSPER电流需要比WT KSPER更多的正电压和更高的pH。这些结果确立了LRRC 52在KSPER通道中的关键作用，并证明了非成孔辅助亚基的丧失导致严重的生育力损害。此外，通过分析几种基因型，影响KSPER电流特性，我们表明，在体外受精能力与净KSPER电导可用于激活生理条件下。
Significance Mammalian sperm fertility depends on coordinated activation of two sperm-specific ion channels, the alkalization-activated Ca2+-permeable sperm channel and a sperm pH-regulated K+ current (KSPER) channel; both are required for fertility. In the mouse, the KSPER channel is thought to involve a complex of a pore-forming ion channel protein and subunit encoded by the slo3 gene subunit and the leucine-rich-repeat-containing protein 52 (LRRC52) auxiliary subunit. We now show that KO of LRRC52 results in severely compromised fertility and shifts KSPER current activation away from the physiological range. Furthermore, utilizing genotypes with differing average amounts of KSPER current, we show that sperm fertility exhibits a steep dependence on the amount of available KSPER current. The results establish that LRRC52 is a critical determinant of sperm KSPER function and essential to support normal fertility. Following entry into the female reproductive tract, mammalian sperm undergo a maturation process termed capacitation that results in competence to fertilize ova. Associated with capacitation is an increase in membrane conductance to both Ca2+ and K+, leading to an elevation in cytosolic Ca2+ critical for activation of hyperactivated swimming motility. In mice, the Ca2+ conductance (alkalization-activated Ca2+-permeable sperm channel, CATSPER) arises from an ensemble of CATSPER subunits, whereas the K+ conductance (sperm pH-regulated K+ current, KSPER) arises from a pore-forming ion channel subunit encoded by the slo3 gene (SLO3) subunit. In the mouse, both CATSPER and KSPER are activated by cytosolic alkalization and a concerted activation of CATSPER and KSPER is likely a common facet of capacitation-associated increases in Ca2+ and K+ conductance among various mammalian species. The properties of heterologously expressed mouse SLO3 channels differ from native mouse KSPER current. Recently, a potential KSPER auxiliary subunit, leucine-rich-repeat-containing protein 52 (LRRC52), was identified in mouse sperm and shown to shift gating of SLO3 to be more equivalent to native KSPER. Here, we show that genetic KO of LRRC52 results in mice with severely impaired fertility. Activation of KSPER current in sperm lacking LRRC52 requires more positive voltages and higher pH than for WT KSPER. These results establish a critical role of LRRC52 in KSPER channels and demonstrate that loss of a non-pore-forming auxiliary subunit results in severe fertility impairment. Furthermore, through analysis of several genotypes that influence KSPER current properties we show that in vitro fertilization competence correlates with the net KSPER conductance available for activation under physiological conditions.