Lymphocyte calmodulin and its participation in the stimulation of T lymphocytes by mitogenic lectins.
Calmodulin was purified from human tonsillar lymphocytes utilizing calcium-dependent binding of calmodulin to fluphenazine-Sepharose. The molecular weight and phosphodiesterase activation of the lymphocyte calmodulin were very similar to those of purified bovine brain calmodulin. Trifluoperazine (TFP), a calmodulin inhibitor, suppressed lymphocyte stimulation as assessed by 3H-thymidine incorporation into DNA of lectin-stimulated lymphocytes. TFP had no effect on the early 45Ca2+ uptake induced by mitogenic lectins, although this latter was inhibited by verapamil which also suppressed the 3H-thymidine incorporation. The results are in keeping with the interpretation that the inhibition of T cell stimulation by TFP was not due to suppression of Ca2+ uptake, but due to inactivation of Ca(2+)-calmodulin complex which might be formed subsequent to Ca2+ entry into the cell.
Nakabayashi
H
H
Department of Pathology, Mie University School of Medicine, Japan.
Komada
H
H
Yoshida
T
T
Takanari
H
H
Izutsu
K
K
D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D066298:In Vitro Techniques; D037102:Lectins / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D014268:Trifluoperazine / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D002147:Calmodulin; D037102:Lectins; D014268:Trifluoperazine; D014700:Verapamil; D002118:Calcium