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Lymphocyte calmodulin and its participation in the stimulation of T lymphocytes by mitogenic lectins
Author(s) -
Nakabayashi Hiroshi,
Komada Hiroshi,
Yoshida Toshimichi,
Takanari Hideki,
Izutsu Kosaku
Publication year - 1992
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/0248-4900(92)90124-j
Subject(s) - calmodulin , trifluoperazine , biology , concanavalin a , stimulation , verapamil , calcium , fluphenazine , phytohaemagglutinin , lymphocyte , biochemistry , thymidine , dna synthesis , phosphodiesterase , lectin , calmodulin binding proteins , microbiology and biotechnology , medicine , endocrinology , dna , immunology , in vitro , enzyme , dopamine , haloperidol
Summary— 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 3 H‐thymidine incorporation into DNA of lectin‐stimulated lymphocytes. TFP had no effect on the early 45 Ca 2+ uptake induced by mitogenic lectins, although this latter was inhibited by verapamil which also suppressed the 3 H‐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 Ca 2+ uptake, but due to inactivation of Ca 2+ ‐calmodulin complex which might be formed subsequent to Ca 2+ entry into the cell.