MEMBRANE POTENTIAL AND CROSSTALK IN SPERM CAPACITATION

哺乳动物的精子在射精后不能立即使卵子受精。他们 在女性生殖道中居住一段时间后获得受精能力， 时间女性生殖道发生的生理变化， 能够受精的精子构成“精子获能”现象。 已经证明，获能与 一部分蛋白质的酪氨酸磷酸化增加。它还 已经证明，蛋白质酪氨酸磷酸化的增加是 由涉及蛋白激酶A（PKA）的cAMP依赖性途径调节。 精子质膜的超极化也与 获能据推测，超极化的精子血浆， 在获能过程中，膜在某种程度上与cAMP依赖性 蛋白质的磷酸化。这项修订建议的目的是 阐明反应的顺序及其机制， 小鼠精子获能过程中超极化。以下具体 目的是：1）阐明媒体成分在调节中的作用 精子膜电位和获能; 2）确定 膜超极化、cAMP和蛋白酪氨酸磷酸化;以及3） 为了确定精子细胞中显示信号转导的区域， 获能

Mammalian sperm are not able to fertilize eggs immediately after ejaculation. They acquire fertilization capacity after residing in the female tract for a finite period of time. The physiological changes occuring in the female reproductive tract that render the sperm able to fertilize constitute the phenomenon of "sperm capacitation". It has been demonstrated that capacitation is associated with an increase in the tyrosine phosphorylation of a subset of proteins. It has also been demonstrated that the increase in protein tyrosine phosphorylation is regulated by a cAMP-dependent pathway involving protein kinase A (PKA). Hyperpolarization of the sperm plasma membrane has also been associated with capacitation. It is hypothesized that hyperpolarization of sperm plasma membrane during capacitation is, in some way, related to the cAMP-dependent phosphorylation of proteins. The objectives of this amended proposal are to elucidate the sequence of reactions and their mechanisms leading to hyperpolarization of mouse sperm during capacitation. The following specific aims are proposed: 1) to elucidate the role of media components in regulating sperm membrane potential and capacitation; 2) to determine the link between membrane hyperpolarization, cAMP and protein tyrosine phosphorylation; and 3) to define the regions of the sperm cell that display signal transduction during capacitation.