Characterization of calcineurin (Cn) in human lung mast cells (HLMC) and basophils

Peachell, P.T., Peirce, M.J. and Munday, M. (1998) Characterization of calcineurin (Cn) in human lung mast cells (HLMC) and basophils. FASEB Journal, 12 (5). A896.

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The immunosuppressants, cyclosporin A (CsA) and FK506, have been shown to inhibit the IgE-mediated release of mediators from HLMC and basophils (eg De Paulis et al., J Immunol 147; 4278, 1991). Because CsA and FK506 inhibit the Ca2+-dependent phosphatase (PP), Cn, these data suggest that Cn may regulate HLMC and basophil responses. Immuno blotting of solubilized preparations of purified (> 90% purity) cells was performed employing a monoclonal antibody to the B chain of Cn. These experiments (n=4) indicated that CnB (19 kDa) is present in HLMC and basophils. Mononuclear cells (MNC) and Jurkat cells (T lymphocytes) were also found to contain CnB by this method. Densitometry of the blots indicated that, on a per cell basis, HLMC contain 1.8, 2.3 and 9.6 fold more CnB than Jurkat cells, MNC and basophils, respectively. Extracts of HLMC, MNC and basophils liberated 32P, in a calcium-dependent manner, from a synthetic peptide which acts as a substrate for Cn (n=4). HLMC contained the highest levels of Ca2+-dependent PP activity (12.8±3 pmol 32P liberated by 1x106 HLMC per min) and this activity was 2.4 and 7.1 fold higher than the PP activities detected in MNC and basophils, respectively. Neither CsA (1 ?M) nor FK506 (100 nM) inhibited the Ca2+-dependent PP activities present in extracts of the 3 cell types (n=3). These data indicate that HLMC and basophils contain, (i) CnB and (ii) a Ca2+-dependent PP activity. However, the quantity of CnB and the extent of the PP activity was about 8 fold higher in HLMC than in basophils.

Item Type:Article
Departments, units and centres:Department of Pharmaceutical and Biological Chemistry > Department of Pharmaceutical and Biological Chemistry
ID Code:3011
Journal or Publication Title:FASEB Journal
Deposited By:Library Staff
Deposited On:22 Mar 2012 11:21
Last Modified:22 Mar 2012 11:21

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