Supramolecular organization of the sperm plasma membrane during maturation and capacitation
Supramolecular organization of the sperm plasma membrane during maturation and capacitation作者机构：The Babraham Institute Cambridge CB2 4AT UK Department of Chemistry University of Cambridge Cambridge CB2 1EW UK
出 版 物：《Asian Journal of Andrology》 (亚洲男性学杂志（英文版）)
年 卷 期：2007年第9卷第4期
页 面：438-444页
核心收录：
学科分类：1002[医学-临床医学] 1001[医学-基础医学(可授医学、理学学位)] 10[医学]
基 金：This work was supported by the Biotechnology and Biological Sciences Research ouncil(UK)
主 题：cholesterol lipid rafts single molecules sperm membranes
摘 要：Aim： In the present study, a variety of high resolution microscopy techniques were used to visualize the organization and motion of lipids and proteins in the sperm＇s plasma membrane. We have addressed questions such as the presence of diffusion barriers, confinement of molecules to specific surface domains, polarized diffusion and the role of cholesterol in regulating lipid rafts and signal transduction during capacitation. Methods： Atomic force microscopy identified a novel region （EqSS） within the equatorial segment of bovine, porcine and ovine spermatozoa that was enriched in constitutively phosphorylated proteins. The EqSS was assembled during epididymal maturation. Fluorescence imaging techniques were then used to follow molecular diffusion on the sperm head. Results： Single lipid molecules were freely exchangeable throughout the plasma membrane and showed no evidence for confinement within domains. Large lipid aggregates, however, did not cross over the boundary between the post-acrosome and equatorial segment suggesting the presence of a molecular filter between these two domains. Conclusion： A small reduction in membrane cholesterol enlarges or increases lipid rafts concomitant with phosphorylation of intracellular proteins. Excessive removal of cholesterol, however, disorganizes rafts with a cessation of phosphorylation. These techniques are forcing a revision of long-held views on how lipids and proteins in sperm membranes are assembled into larger complexes that mediate recognition and fusion with the egg. （Asian JAndrol 2007 July; 9： 438-444）
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