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TPCK inhibits AGC kinases by direct activation loop adduction at phenylalanine‐directed cysteine residues
Author(s) -
Anjum Rana,
Pae Eunice,
Blenis John,
Ballif Bryan A.
Publication year - 2012
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/j.febslet.2012.07.075
Subject(s) - kinase , cysteine , phenylalanine , chemistry , protein kinase b , biochemistry , microbiology and biotechnology , phosphorylation , biology , enzyme , amino acid
N‐alpha‐tosyl‐ l ‐phenylalanyl chloromethyl ketone (TPCK) has anti‐tumorigenic properties, but its direct cellular targets are unknown. Previously, we showed TPCK inhibited the PDKl‐dependent AGC kinases RSK, Akt and S6K1 without inhibiting PKA, ERK1/2, PI3K, and PDK1 itself. Here we show TPCK‐inhibition of the RSK‐related kinases MSK1 and 2, which can be activated independently of PDK1. Mass spectrometry analysis of RSK1, Aktl, S6K1 and MSK1 immunopurified from TPCK‐treated cells identified TPCK adducts on cysteines located in conserved activation loop Phenylalanine–Cysteine (Phe–Cys) motifs. Mutational analysis of the Phe–Cys residues conferred partial TPCK resistance. These studies elucidate a primary mechanism by which TPCK inhibits several AGC kinases, inviting consideration of TPCK‐like compounds in chemotherapy given their potential for broad control of cellular growth, proliferation and survival.