Activation-induced proteolysis of cytoplasmic domain of zeta in T cell receptors and Fc receptors.
The CD3-T cell receptor (TCR) complex on T cells and the Fc gamma receptor type III (Fc gamma RIII)-zeta-gamma complex on natural killer cells are functionally analogous activation receptors that associate with a family of disulfide-linked dimers composed of the related subunits zeta and gamma. Immunochemical analysis of receptor complexes separated on two-dimensional diagonal gels allowed the identification of a previously uncharacterized zeta-p14 heterodimer. zeta-p14 is a component of both CD3-TCR and Fc gamma RIII-zeta-gamma. Peptide mapping analysis shows that p14 is structurally related to zeta, suggesting that it is either: (i) derived from zeta proteolytically or (ii) the product of an alternatively spliced mRNA. The observation that COS cells transformed with a cDNA encoding zeta express zeta-p14 supports the former possibility. The expression of CD3-TCR complexes including zeta-p14 increases following activation with phorbol 12-myristate 13-acetate or concanavalin A, suggesting that proteolysis of zeta may contribute to receptor modulation or desensitization.
Taupin
J L
JL
Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA 02115.
Anderson
P
P
D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010449:Peptide Mapping; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D011961:Receptors, Fc / Q000378:metabolism*; D015398:Signal Transduction
D008565:Membrane Proteins; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D011961:Receptors, Fc; C054979:antigen T cell receptor, zeta chain