Expression and localization of five members of the testis-specific serine kinase (Tssk) family in mouse and human sperm and testis.
Members of the testis-specific serine/threonine kinases (Tssk) family may have a role in sperm differentiation in the testis and/or fertilization. To gain insight into the functional relevance of these kinases, their expression was examined both at the mRNA and protein levels. Quantitative PCR analysis confirmed that all five Tssk mRNAs are almost exclusively expressed postmeiotically in the testis. Recombinant mouse and human Tssks were cloned and used for validation of an array of commercial and custom-made antibodies against Tssks. Immunolocalization in mouse testis, and in mouse and human sperm, showed that Tssk1, Tssk2, Tssk4 and Tssk6, but not Tssk3, were present in mouse sperm and in germ cells from mouse testis. TSSK1, TSSK2 and TSSK6 were also detected in human sperm, while TSSK3 was absent. In both mouse and human sperm, Tssk1 was partially soluble, while Tssk2, Tssk4 and Tssk6 were insoluble in non-ionic detergents. In vitro recombinant TSSK2 activity assays showed maximum enzymatic activity at 5 mM Mg(2+) and a Km for ATP of ∼10 µM. These, observations together with findings that the Tssk1/Tssk2 double knock-out as well as the Tssk6 null mice are sterile without presenting other detectable defects, suggest that these kinases could be used as targets for male contraception.
Li
Yahui
Y
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, USA.
Sosnik
Julian
J
Brassard
Laura
L
Reese
Michael
M
Spiridonov
Nikolay A
NA
Bates
Tonya C
TC
Johnson
Gibbes R
GR
Anguita
Juan
J
Visconti
Pablo E
PE
Salicioni
Ana M
AM
D000818:Animals; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013087:Spermatids / Q000201:enzymology; D013094:Spermatozoa / Q000201:enzymology*; D013737:Testis / Q000201:enzymology*
C497812:TSSK2 protein, human; D017346:Protein Serine-Threonine Kinases