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Regulation of microtubule sliding by a 36‐kDa phosphoprotein in hamster sperm flagella
Author(s) -
Si Yuming,
Okuno Makoto
Publication year - 1999
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199903)52:3<328::aid-mrd11>3.0.co;2-n
Subject(s) - motility , biology , flagellum , microbiology and biotechnology , hamster , sperm motility , sperm , microtubule , phosphorylation , biochemistry , genetics , gene
Cyclic AMP has been shown essential for activation of sperm motility. When immotile hamster caudal epididymal spermatozoa were suspended in a Ca 2+ ‐deficient solution, they showed a sluggish motility. Spermatozoa were demembranated and transferred to an ATP‐containing reactivation solution. Demembranated spermatozoa did not exhibit reactivated flagellar movement unless cAMP was added. Conversely, when the immotile epididymal spermatozoa were suspended in a Ca 2+ ‐containing solution, they were immediately activated to display a vigorous motility; demembranated spermatozoa also exhibited reactivated flagellar movement in the reactivation solution without cAMP. Further investigation of microtubule sliding properties revealed that the effects of Ca 2+ on live spermatozoa were identical with the effects of cAMP on demembranated spermatozoa both in microtubule sliding velocity and sliding disintegration pattern. Moreover, a 36‐kDa flagellar protein was found to be phosphorylated in a cAMP‐dependent manner and coupled to the motility activation. A polyclonal antibody against this protein was developed and showed specific immunolocalization and significant inhibitory effects on microtubule sliding disintegration. These results indicate that extracellular Ca 2+ owes its effect to triggering intracellular cAMP production, and cAMP‐dependent phosphorylation of a 36‐kDa phosphoprotein activates hamster sperm motility through regulation of microtubule sliding properties. Mol. Reprod. Dev. 52:328–334, 1999. © 1999 Wiley‐Liss, Inc.