手机知网 App
24小时专家级知识服务
打 开
手机知网|搜索

Sio3 is the channel mediating KSper potassium current in sperm

Xuhui Zeng~* Institute of Life Science.Nanchang University;Nanchang;Jiangxi Province;330031

  Slo3 channel is the primary candidate mediating the pH-dependent K~+ current (KSper) in mouse sperm.However,because heterologous expression of Slo3 results in currents that are much less activated at physiological conditions that are native KSper currents,the equivalence of Slo3-dependent current and KSper remains uncertain.Here, we show that genetic deletion of Slo3 abolishes all pH-dependent K~+ current at physiological membrane potentials in corpus epididymal sperm.At potentials above 0 mV, a residual pH-dependent outward current(I_(Kres)) is observed in Slo3-/-sperm.Differential inhibition of KSper/Slo3 and I_(Kres) by clofilium reveals that the amplitude of I_(Kres) is similar in both wt and Slo3-/-sperm,strongly supporting the idea that I_(Kres) is an intrinsic component in native sperm.The properties of I_(Kres) suggest that it likely represents outward monovalent cation flux through CatSper channels.Thus.KSper/Slo3 may account for essentially all mouse sperm K~+ current and is the sole pH-dependent K~+ conductance in these sperm.With deletion of Slo3.the sperm exhibit deficits from distinct aspects, including membrane potential response to alkalization.motility in the absence of bicarbonate,and morphological adaption under hypotonic challenge.As a consequence, Slo3-/-male mice are infertile.Together these results show that KSper/Slo3 is the primary spermatozoan K~+ current which is critical for normal sperm function.Our results also suggest that Slo3 channel is a potential target for developing male contraceptives.……