CAMP/PKA‐mediated regulation of amino acid metabolism in murine T‐lymphoma cells (1095.16)

Abstract

The second messenger cyclic AMP (cAMP), acting through PKA, influences gene and protein expression through CREB and other transcription factors. In order to define the proteins whose expression is regulated by cAMP and protein kinase A (PKA), we conducted quantitative proteomic studies of wild‐type (WT) and kin‐ (PKA‐null) S49 murine T lymphoma cells and compared the impact on protein expression of increases in cAMP by a cell‐permeable analog (8‐CPT‐cAMP, CPT). Numerous proteins involved in branched chain amino acid metabolism had markedly increased expression in WT S49 cells, but not kin‐ cells, treated with CPT for 16h. Expression of mRNA levels of these genes also increased in WT, but not kin‐, S49 cells in response to treatment with CPT. Consistent with this finding, incubation of WT S49 cells with CPT enhanced cell survival in growth media lacking glutamine, whereas kin‐ S49 cells show decreased viability in such media even in the presence of 8‐CPT‐cAMP. We conclude that cAMP acts via PKA to regulate expression of genes and proteins for branched chain amino acids, an action that may help protect cells from a decrease in viability in glutamine‐deficient media. Since not all of the cAMP/PKA‐regulated branched chain amino acid metabolism genes with increased expression have strong predicted binding of CREB, regulation of those genes by cAMP/PKA appears to occurs through as‐yet to be defined transcriptional pathways.Grant Funding Source: Supported by HHMI (S. S.T.), and DK54441 (S.S.T.), GM066232 (P.A.I.) and HL107200 (P.A.I.) from NIH