Possible participation of calmodulin in stimulation of leucine transport by concanavalin A in human lymphocytes.
Stimulation of leucine uptake by addition of concanavalin A, mediated by increase of intracellular free Ca2+ concentration [( Ca2+]), in lymphocytes (Mitsumoto, Y., Sato, K. and Mohri, T. (1988) Biochim. Biophys. Acta 968, 353-358) was abolished by N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) and chlorpromazine, which inhibited membrane hyperpolarization induced by the mitogen. Quinine (0.5-1 mM) completely inhibited the concanavalin A-induced hyperpolarization and extensively inhibited the induced stimulation of leucine uptake. Based on these results, we suggest that the stimulation of leucine uptake by concanavalin A is largely due to activation of the Ca2+-dependent K+ channel which reinforces negative potential of the plasma membrane and is regulated by calmodulin.
Sato
K
K
2nd Division, Hokuriku University School of Pharmacy, Ishikawa, Japan.
Mitsumoto
Y
Y
Mohri
T
T
D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000502:physiology*; D002746:Chlorpromazine / Q000494:pharmacology; D003208:Concanavalin A / Q000494:pharmacology; D003975:Diazepam / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D007930:Leucine / Q000378:metabolism*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000502:physiology*; D011803:Quinine / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology
D002147:Calmodulin; D007473:Ion Channels; D013449:Sulfonamides; D003208:Concanavalin A; D000001:Calcimycin; C017967:W 7; C034700:N-(6-aminohexyl)-1-naphthalenesulfonamide; D011803:Quinine; D007930:Leucine; D003975:Diazepam; D011188:Potassium; D002118:Calcium; D002746:Chlorpromazine