Bracho G E, Fritch J J, Tash J S
Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City 66160-7401, USA.
Biochem Biophys Res Commun. 1998 Jan 6;242(1):231-7. doi: 10.1006/bbrc.1997.7937.
Protein phosphorylation appears to be a necessary step in the intracellular signaling pathway that initiates the activation of sperm motility. Activation of live immotile sea urchin sperm produced rapid, time-dependent increased phosphorylation on proteins of 32, 45, 130, and 500 kDa. Fractionation of immotile and motile sperm indicated that these motility-related phosphoproteins are associated with flagella. These proteins showed greater phosphorylation in the flagellar fraction from motile sperm, suggesting that subcellular boundaries are in place to keep protein kinases and their substrates spatially separated. Solubility properties suggest that these proteins are the heavy chain and smaller subunits of sea urchin sperm dynein which are phosphorylated in vivo to initiate activation of motility. This also suggests that phosphorylation of only these few proteins, out of the nearly 100 phosphorylations known to occur in the basic axoneme, appears to be associated with the early signaling pathways of motility activation in intact sperm.
蛋白质磷酸化似乎是细胞内信号通路中启动精子运动激活的必要步骤。激活活的不动海胆精子会使32、45、130和500 kDa蛋白质上的磷酸化迅速且随时间增加。对不动和活动精子进行分级分离表明，这些与运动相关的磷蛋白与鞭毛相关。这些蛋白质在活动精子的鞭毛部分显示出更高的磷酸化，这表明亚细胞边界的存在是为了使蛋白激酶及其底物在空间上分离。溶解性特性表明，这些蛋白质是海胆精子动力蛋白的重链和较小亚基，它们在体内被磷酸化以启动运动激活。这也表明，在已知发生在基本轴丝中的近100次磷酸化中，只有这少数几种蛋白质的磷酸化似乎与完整精子中运动激活的早期信号通路相关。
