Identification of insulin-like growth factor (IGF)-1 receptor in human sperm cell.
The present study was conducted to examine the presence of insulin-like growth factor- receptor (IGF-1R) in human sperm cell. The IGF-1R monoclonal antibody (MAb) specifically immunoprecipitated two protein bands of approximately 135 and approximately 220 kD, respectively, from the reduced human sperm extract. These bands correspond to the alpha-subunit and partially reduced IGF-1R molecule, respectively. The immunocytochemistry experiments indicated the presence of IGF-1R primarily in the equatorial regions, along with a weak binding in the acrosomal regions of human spermatozoa. These data indicate that the IGF-1 receptor is present in the human sperm cell. Since the IGF-1 receptor has tyrosine kinase activity and its ligand IGF-1 is present in the seminal plasma, the IGF-1 system (IGF-1R/IGF-1/IGF-binding protein) may be involved in the signal transduction pathway leading to sperm capacitation and acrosome exocytosis.
Naz
R K
RK
Department of Obstetrics and Gynecology, Medical College of Ohio, Toledo 43614-5806, USA. rnaz@mco.edu
Padman
P
P
D000177:Acrosome / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008297:Male; D017526:Receptor, IGF Type 1 / Q000276:immunology / Q000378:metabolism*; D013094:Spermatozoa / Q000166:cytology / Q000276:immunology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D017526:Receptor, IGF Type 1