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Assembly of the CD8α/p56 lck protein complex in stably expressing rat epithelial cells
Author(s) -
Pascale M.C.,
Remondelli P.,
Leone A.,
Bonatti S.
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01945-1
Subject(s) - immunoprecipitation , biogenesis , microbiology and biotechnology , chemistry , phosphorylation , cell culture , biology , biochemistry , gene , genetics
We have previously characterized the biogenesis of the human CD8α protein expressed in rat epithelial cells. We now describe the biosynthesis, post‐translational maturation and hetero‐oligomeric assembly of the human CD8α/p56 lck protein complex in stable transfectants obtained from the same cell line. There were no differences in the myristilation of p56 lck , or in the dimerization, O ‐glycosylation and transport to the plasma membrane of CD8α, between cells expressing either one or both proteins. In the doubly expressing cells, dimeric forms of CD8α established hetero‐oligomeric complexes with p56 lck , as revealed by co‐immunoprecipitation assays performed with anti‐CD8α antibody. Moreover, p56 lck bound in these hetero‐oligomeric complexes was endowed with auto‐ and hetero‐phosphorylating activity. The present study shows that: (1) the newly synthesized p56 lck binds rapidly to CD8α and most of the p56 lck is bound to CD8α at steady state; (2) CD8α/p56 lck protein complexes are formed at internal membranes as well as at the plasma membrane; and (3) about 50% of complexed p56 lck reaches the cell surface.