Microtubule sliding movement in tilapia sperm flagella axoneme is regulated by Ca2+/calmodulin-dependent protein phosphorylation

• DOI: 10.1002/cm.20137
• Publication Date: 2006-06-09T18:34:51Z
• Authors: Masaya Morita; Akihiro Takemura; Ayako Nakajima; Makoto Okuno
• Keywords: Axoneme

Demembranated euryhaline tilapia Oreochromis mossambicus sperm were reactivated in the presence of concentrations excess 10−6 M Ca2+. Motility features changed when Ca2+ increased from to 10−5 M. Although beat frequency did not increase, shear angle and wave amplitude flagellar beating increased, suggesting that sliding velocity microtubules axoneme, which represents dynein activity, rises with an increase Thus, it is possible binds proteins activate motility as a result enhanced activity. One Ca2+-binding protein (18 kDa, pI 4.0), calmodulin (CaM), was detected by 45Ca overlay assay immunologically. A CaM antagonist, W-7, suppressed reactivation ratio swimming speed, 18 kDa regulates motility. CaMKIV immunologically single 48 band both fraction low ion extract axoneme remnant distinct positions axoneme. It phosphorylates axonemal Ca2+/CaM-dependent manner for regulating 32P-uptake showed 48, 75, 120, 200, 250, 380, 400 phosphorylated Ca2+/CaM kinase-dependent manner. Proteins (380 kDa) induces regulation, including phosphorylation activation/regulation activity Cell Motil. Cytoskeleton 2006. © 2006 Wiley-Liss, Inc.