Primate sperm contain protein phosphatase 1, a biochemical mediator of motility
Primate sperm contain protein phosphatase 1, a biochemical mediator of motility
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DOI：
10.1095/biolreprod54.3.719
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发表时间：
1996-03-01
影响因子：
3.6
通讯作者：
Vijayaraghavan, S
中科院分区：
文献类型：
--
作者：
Smith, GD;Wolf, DP;Vijayaraghavan, S
精子的运动起始、获能和超激活是由细胞内Ca2+、cAMP和ph的相互作用调节的。这些介质改变精子功能的机制尚未阐明，但可能涉及调节蛋白磷酸化的可逆改变。本研究旨在1)研究蛋白磷酸酶（PP）抑制剂calyculin A （CA）对人类精子活力的影响；2)研究人类和恒河猴精子中对CA敏感的PP及其内源性调节剂。CA （50 nM）处理人类精子导致运动百分比的增加和平均路径速度的加速。蛋白磷酸酶-1 （PP1）或蛋白磷酸酶- 2a （PP2A）的抑制可能是这种运动刺激的原因，因为这两种磷酸酶都对纳摩尔量的CA敏感。在没有二价阳离子的情况下，使用PP1和PP2A的首选底物[P-32]-磷酸化酶-a测量了人类（n = 4）和恒河猴（n = 4）精子的PP活性。人类(6.2 +/- 4.5 × 10（-2) mU/10(8)精子）和猴子(4.3 +/- 0.8 × 10（-2) mU/10(6)精子）的超声波含有活性，根据对冈田酸（OA）和CA的抑制谱初步鉴定为PP1。随后，针对PP1各种亚型抗体的Western blot分析证实PP1（γ 2）在人类和猴子精子中存在。PP1在大多数组织中的活性受热稳定抑制剂I1或I2的调节。精子声索含有类似I2的抑制剂活性以及参与PP1-I2复合物激活的糖原合成酶激酶-3 （GSK-3）活性。这些结果首次表明，人类和恒河猴精子中含有PP1和PP1的调节因子，并且CA抑制PP1活性可以增强精子的运动性。
Sperm motility initiation, capacitation, and hyperactivation are modulated by an interplay of intracellular Ca2+, cAMP, and pH. Mechanisms by which these mediators alter sperm function have not been elucidated but may involve reversible alterations in regulatory protein phosphorylation. Studies were designed 1) to investigate the influence of the protein phosphatase (PP) inhibitor calyculin A (CA) on human sperm motility and 2) to characterize the CA-sensitive PP and its endogenous regulators in human and rhesus monkey sperm. CA (50 nM) treatment of human sperm resulted in an increase in percentage motility and an acceleration in mean path velocity. Inhibition of either protein phosphatase-1 (PP1) or protein phosphatase-2A (PP2A) could be responsible for this motility stimulation, since both of these phosphatases are sensitive to nanomolar quantities of CA. PP activity in human (n = 4) and rhesus monkey (n = 4) sperm sonicates was measured using [P-32]-phosphorylase-a, the preferred substrate for PP1 and PP2A, in the absence of divalent cations. Human (6.2 +/- 4.5 x 10(-2) mU/10(8) sperm) and monkey (4.3 +/- 0.8 x 10(-2) mU/10(6) sperm) sonicates contained activity tentatively identified as PP1 on the basis of inhibition profiles in okadaic acid (OA) and CA. Western blot analysis with antibodies against various isoforms of PP1 subsequently documented the presence of PP1(gamma 2) in human and monkey sperm. PP1 activity in most tissues is regulated by the heat-stable inhibitors I1 or I2. Sperm sonicates contained inhibitor activity similar to I2 as well as glycogen synthase kinase-3 (GSK-3) activity, which is involved in the activation of the PP1-I2 complex. These results indicate, for the first time, that human and rhesus monkey sperm contain PP1 and regulators of PP1 and that inhibition of PP1 activity by CA can enhance motility.