期刊
MOLECULAR HUMAN REPRODUCTION
卷 19, 期 12, 页码 852-864出版社
OXFORD UNIV PRESS
DOI: 10.1093/molehr/gat070
关键词
sperm; PLC-zeta; calcium oscillations; egg activation; fertilization
资金
- Wellcome Trust [080701]
- NCSR Demokritos
- Libyan Government
Phospholipase C-zeta (PLC?) is a sperm-specific protein believed to cause Ca-2 oscillations and egg activation during mammalian fertilization. PLC? is very similar to the somatic PLC1 isoform but is far more potent in mobilizing Ca-2 in eggs. To investigate how discrete protein domains contribute to Ca-2 release, we assessed the function of a series of PLC?/PLC1 chimeras. We examined their ability to cause Ca-2 oscillations in mouse eggs, enzymatic properties using in vitro phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis and their binding to PIP2 and PI(3)P with a liposome interaction assay. Most chimeras hydrolyzed PIP2 with no major differences in Ca-2 sensitivity and enzyme kinetics. Insertion of a PH domain or replacement of the PLC? EF hands domain had no deleterious effect on Ca-2 oscillations. In contrast, replacement of either XY-linker or C2 domain of PLC? completely abolished Ca-2 releasing activity. Notably, chimeras containing the PLC? XY-linker bound to PIP2-containing liposomes, while chimeras containing the PLC? C2 domain exhibited PI(3)P binding. Our data suggest that the EF hands are not solely responsible for the nanomolar Ca-2 sensitivity of PLC? and that membrane PIP2 binding involves the C2 domain and XY-linker of PLC?. To investigate the relationship between PLC enzymatic properties and Ca-2 oscillations in eggs, we have developed a mathematical model that incorporates Ca-2-dependent InsP(3) generation by the PLC chimeras and their levels of intracellular expression. These numerical simulations can for the first time predict the empirical variability in onset and frequency of Ca-2 oscillatory activity associated with specific PLC variants.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据