Regulation of fowl sperm flagellar motility by protein phosphatase type 1 and its relationship with dephosphorylation of axonemal and/or accessory cytoskeletal proteins

The motility of demembranated fowl spermatozoa was vigorous at 30 degrees C in the presence of ATP, but decreased markedly following the addition of recombinant protein phosphatase type 1 (PP-1) supplemented with Mn2+. This inhibition was not restored by the addition of cAMP, within the range 1-1000 mu M, but instantly restored by the addition of 50 ng/ml trypsin. Phosphorylation of demembranated fowl sperm proteins during incubation with [gamma-P-32]ATP at 30 degrees C was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A marked difference in phosphorylation status was observed in approximately 116, 86, 79, 50 and 29-kDa proteins. These proteins were dephosphorylated in the presence of PP-1 and Mn2+ compared with those in control samples. These results suggest that PP-1-mediated dephosphorylation of some of these proteins of the axoneme and/or accessory cytoskeletal components of fowl spermatozoa may be involved in the inhibition of motility. (C) 1997 Academic Press.