Multiple Pathways Regulate Na+-H+ Antiporter in the Sea Urchin Egg and Early Embryo

钙和质子两种离子的变化在受精过程中具有重要意义。钙离子活性的增加和质子活性的降低是孤雌生殖，而受精过程中抑制正常变化阻碍了发育。过去的研究已经证明了卵膜中磷脂酰肌醇4，5-二磷酸的第二信使途径，类似于哺乳动物细胞增殖过程中提出的途径。对受精过程中离子通量控制的进一步分析提出了另一种调控途径，该途径独立于肌醇类脂水解物。这项拟议的研究旨在确定这一替代调控途径。人们的注意力集中在可能的钙-钙调蛋白依赖的蛋白激酶调节上。在丝裂原刺激的哺乳动物细胞增殖过程中，对离子通量的多种调节途径也已有报道。有一类重要的有丝分裂原不需要肌醇类脂水解物，其受体具有酪氨酸激酶活性。磷酸化-去磷酸化被认为是一种重要的细胞调控机制。蛋白质磷酸化的稳定状态取决于该蛋白质所特有的激酶和磷酸酶的活性。在海胆卵中测定了酪氨酸磷酸酶和磷酸酶抑制物的活性。将调查它们在受精过程中可能采取的调控行动。最后，受精的一个新特征是形成酸性隔间。描述了分离这些细胞器的程序，并将其用于表征酸室的形成。卵子受精启动了一系列戏剧性的过程，导致静止的卵子代谢变得非常活跃，并开始分裂。最早的变化之一是细胞内钙离子和氢离子活性的变化。这项研究旨在研究这些变化，并将已知的与调节哺乳动物细胞分裂有关的类似变化联系起来。

The changes of two ions, calcium and proton, are of importance in fertilization . Increasing calcium activity and decreasing proton activity are parthenogenetic, while suppression of the normal changes during fertilization blocks development. Past research has demonstrated a second messenger pathway initiated with hydrolysis of phosphatidylinositol 4,5-bisphosphate in the egg membrane, similar to that suggested during mammalian cell proliferation. Further analysis of the control of ion fluxes during fertilization suggests another regulatory pathway, which is independent of inositol lipid hydrolysis. The proposed research is directed towards the identification of this alternative regulatory pathway. Attention is focused towards possible calcium-calmodulin dependent protein kinase regulation. Multiple regulatory pathways on ionic fluxes during mitogen stimulated mammalian cell proliferation have also been reported. An important group of mitogen that do not require inositol lipid hydrolysis have receptors with tyrosine kinase activity. Phosphorylation-dephosphorylation has been recognized as an important cellular regulatory mechanism. The steady state of phosphorylation of a protein depends upon the kinase and phosphatase activities specific for the protein. Tyrosine phosphatase and phosphatase inhibitor activities have been measured in the sea urchin egg. Their possible regulatory actions during fertilization will be investigated. Finally, a novel feature of fertilization is the formation of acid compartments. A procedure to isolate these organelles is described and is utilized for characterizing the formation of the acid compartment. %%% Fertilization of the egg initiates a dramatic series of that lead to the quiescent egg becoming metabolically very active and its beginning to divide. Among the earliest changes are changes in the intracellular activities of calcium and hydrogen ions. This study is to investigate these changes and to relate similar changes known to be involved in regulating cell division in mammalian cells.