Expression of a Ca2+/calmodulin-dependent protein kinase, CaM kinase-Gr, in human T lymphocytes. Regulation of kinase activity by T cell receptor signaling.

S.H Hanissian,M Frangakis,M.M Bland,S Jawahar,T.A Chatila

doi:10.1016/s0021-9258(20)80693-0

S.H Hanissian, M Frangakis + Show 3 more

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https://doi.org/10.1016/s0021-9258(20)80693-0

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Abstract

Ca2+/calmodulin-dependent protein kinase type Gr (CaM kinase-Gr) is a Ca2+/calmodulin-dependent protein kinase which is enriched in the brain and thymus. In this study, we examined the expression of CaM kinase-Gr in human lymphocytes and the regulation of its catalytic activity by antigen receptor signaling. CaM kinase-Gr was found selectively expressed in T lymphocytes in a developmentally regulated manner. It was present at severalfold higher levels in immature thymocytes (CD3low, CD4+CD8+) relative to mature thymocytes (CD3high, CD4+CD8-/CD8+CD4-) or to circulating T lymphocytes. The kinase was preferentially expressed in CD4+ T lymphocytes, but was not detected in B lymphocytes or in monocytes. The impact of T cell antigen receptor-CD3 complex (TCR.CD3) signaling on kinase activity was examined using Jurkat human leukemic T lymphocytes as a model. Treatment of Jurkat cells with anti TCR.CD3 monoclonal antibody induced rapid autophosphorylation of the kinase on serine residues and a dramatic, autophosphorylation-dependent enhancement of both Ca2+/calmodulin-dependent and autonomous kinase activity. Enzyme autophosphorylation and activation were dependent on the influx of extracellular Ca2+ following receptor signaling but could not be induced by an influx of extra-cellular Ca2+ triggered by ionophores, indicating that additional signals delivered via TCR.CD3 contribute to the activation of CaM kinase-Gr. These findings suggest a role for CaM kinase-Gr in T lymphocyte development and activation and indicate the presence of stringent regulatory mechanisms governing the activity of this kinase in situ.

Highlights

From the $Division of Immunology, The Children’s Hospital and the Departmentof Pediatrics, HarvardMedical School, Boston, Massachusetts 02115 and §The Wellcome Research Laboratories, Research Triangle Park, NorthCarolina 27709
The present studwyas undertaken kat cells with anti TCR*CD3monoclonal antibody in- to examine the expressiopnrofile of CaM kinase-Grin differduced rapidautophosphorylation of thekinaseon ent lymphocyte populations and to determine its participation serine residues and a dramatic, autophosphorylation- in Ca2+signaling initiatedvia lymphocyte antigen receptors
Enzyme au- largely restricted in its expression to the T lymphocyte linetophosphorylation and activation were dependent on age, where itis expressed in adevelopmentallyregulated the influxof extracellular Ca2+ following receptor sigm- anner

Summary

REGULATION OF KINASEACTIVITY BY T CELLRECEPTORSIGNALING*

Inthisstudy,weexaminedtheexpression of CaM binding proteinwhich is comprised of only the regulatory and kinase-Gr in human lymphocytes and the regulaotfion association domains [5,6,7,8]. Antigen receptor-CD3 complex (TCRoCD3) signaling The abundant expressionof CaM kinase-Gr in thymocytes on kinase activity was examined using Jurkat humanpoints to a potentially important function of this enzyme in leukemic T lymphocyteass a model. The present studwyas undertaken kat cells with anti TCR*CD3monoclonal antibody in- to examine the expressiopnrofile of CaM kinase-Grin differduced rapidautophosphorylation of thekinaseon ent lymphocyte populations and to determine its participation serine residues and a dramatic, autophosphorylation- in Ca2+signaling initiatedvia lymphocyte antigen receptors. Suggest a role for CaM kinase-Grin T lymphocyte development and activation and indicate the presence

MATERIALS AND METHODS

The following cell lines were obtained from the American Type

RESULTS

DISCUSSION