Abstract
The small subunit of calpain, a calcium-dependent cysteine protease, was found to interact with the cytoplasmic domain of the common cytokine receptor gamma chain (gammac) in a yeast two-hybrid interaction trap assay. This interaction was functional as demonstrated by the ability of calpain to cleave in vitro-translated wild-type gammac, but not gammac containing a mutation in the PEST (proline, glutamate, serine, and threonine) sequence in its cytoplasmic domain, as well as by the ability of endogenous calpain to mediate cleavage of gammac in a calcium-dependent fashion. In T cell receptor-stimulated murine thymocytes, calpain inhibitors decreased cleavage of gammac. Moreover, in single positive CD4(+) thymocytes, not only did a calpain inhibitor augment CD3-induced proliferation, but antibodies to gammac blocked this effect. Finally, treatment of cells with ionomycin could inhibit interleukin 2-induced STAT protein activation, but this inhibition could be reversed by calpain inhibitors. Together, these data suggest that calpain-mediated cleavage of gammac represents a mechanism by which gammac-dependent signaling can be controlled.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Amino Acid Substitution
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Animals
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Base Sequence
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CD4-Positive T-Lymphocytes / cytology
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CD4-Positive T-Lymphocytes / drug effects
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CD4-Positive T-Lymphocytes / immunology
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Calpain / metabolism*
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Cells, Cultured
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DNA Primers
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Glutamic Acid
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Humans
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Interleukin-2 / pharmacology
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Ionomycin / pharmacology
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Lymphocyte Activation
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Macromolecular Substances
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Mice
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Mice, Inbred C57BL
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Molecular Sequence Data
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Mutagenesis, Site-Directed
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Polymerase Chain Reaction
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Proline
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Protein Biosynthesis
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Receptor-CD3 Complex, Antigen, T-Cell / physiology
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Receptors, Cytokine / biosynthesis
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Receptors, Cytokine / chemistry
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Receptors, Cytokine / metabolism*
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Sequence Alignment
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Serine
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Signal Transduction
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Substrate Specificity
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T-Lymphocytes / cytology
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T-Lymphocytes / drug effects
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T-Lymphocytes / immunology*
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Threonine
Substances
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DNA Primers
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Interleukin-2
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Macromolecular Substances
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Receptor-CD3 Complex, Antigen, T-Cell
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Receptors, Cytokine
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Recombinant Proteins
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Threonine
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Glutamic Acid
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Serine
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Ionomycin
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Proline
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Calpain