Leydig tumor cell protein phosphorylated in response to stimulation with choriogonadotropin or epidermal growth factor is identified as stathmin.
Although hCG and mouse epidermal growth factor activate different signaling systems in a clonal strain of Leydig tumor cells (designated MA-10), both compounds are capable of increasing steroidogenesis, decreasing transcription of the LH/CG receptor gene, and attenuating adenylyl cyclase. We have recently identified a 21-kilodalton protein (p21) that is a potential intermediary in the actions of mouse epidermal growth factor and hCG. Characterization of p21 revealed similarities to stathmin, a ubiquitous phosphoprotein whose phosphorylation is associated with diverse second messenger pathways. Using two different experimental approaches, Western blotting and immunoprecipitation, we present data that identify p21 as stathmin.
Department of Pharmacology, University of Iowa College of Medicine, Iowa City 52242.
S R
SR
Hoelscher
M
M
Ascoli
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D007163:Immunosorbent Techniques; D007984:Leydig Cell Tumor / Q000378:metabolism*; D008297:Male; D051379:Mice; D008868:Microtubule Proteins; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D050777:Stathmin; D014407:Tumor Cells, Cultured
D006063:Chorionic Gonadotropin; D008868:Microtubule Proteins; D010750:Phosphoproteins; D050777:Stathmin; C493994:Stmn1 protein, mouse; D015124:8-Bromo Cyclic Adenosine Monophosphate; D004815:Epidermal Growth Factor