首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Ion channel activity of membrane vesicles released from sea urchin sperm during the acrosome reaction
Authors:Schulz Joseph R  De la Vega-Beltrán Jose L  Beltrán Carmen  Vacquier Victor D  Darszon Alberto
Institution:Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0202, USA.
Abstract:The sperm acrosome reaction (AR) involves ion channel activation. In sea urchin sperm, the AR requires Ca2+ and Na+ influx and K+ and H+ efflux. During the AR, the plasma membrane fuses with the acrosomal vesicle membrane forming hybrid membrane vesicles that are released from sperm into the medium. This paper reports the isolation and preliminary characterization of these acrosome reaction vesicles (ARVs), using synaptosome-associated protein of 25 kDa (SNAP-25) as a marker. Isolated ARVs have a unique protein composition. The exocytosis regulatory proteins vesicle-associated membrane protein and SNAP-25 are inside ARVs, as judged by protease protection experiments, and membrane associated based on Triton X-114 partitioning. ARVs fused with planar bilayers display three main types of single channel activity. The most frequently recorded channel is cationic, weakly voltage dependent and has a low open probability that increases with negative potentials. This channel is activated by cAMP, blocked by Ba2+, and has a PK+/PNa+ selectivity of 4.5. ARVs represent a novel membrane preparation suitable to deepen our understanding of ion channel activity in the AR and during fertilization.
Keywords:Acrosome reaction  Acrosome reaction vesicles  Exocytosis  Fertilization  Planar bilayers  Sea urchin sperm  Sperm ion channels
本文献已被 ScienceDirect PubMed 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号