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An inactive mutant of the α subunit of protein kinase CK2 that traps the regulatory CK2 β subunit
Author(s) -
Cosmelli Diego,
Antonelli Marcelo,
Allende Catherine C,
Allende Jorge E
Publication year - 1997
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(97)00625-x
Subject(s) - casein kinase 2 , protein subunit , protein kinase a , gi alpha subunit , phosphorylation , biochemistry , casein kinase 2, alpha 1 , tetramer , kinase , chemistry , mutant , casein kinase 1 , cyclin dependent kinase complex , biology , microbiology and biotechnology , cyclin dependent kinase 2 , enzyme , gene
Protein kinase CK2 (casein kinase 2) is a ubiquitous Ser/Thr protein kinase involved in cell proliferation. Mutation of the α subunit of the Xenopus laevis CK2 to change aspartic acid 156 to alanine (CK2 α A 156 ) resulted in an inactive enzyme. The CK2 α A 156 mutant, however, binds the regulatory subunit as measured by retention of β on a nickel chelating column mediated by (His) 6 ‐tagged CK2 α A 156 . Addition of CK2 α A 156 also caused β to shift sedimentation in a sucrose gradient from a β 2 dimer (52 kDa) to an α 2 β 2 tetramer (130 000 kDa). CK2 α A 156 can trap the β subunit in an inactive complex reducing the stimulation of casein phosphorylation caused by addition of β to wild‐type α . This competitive effect depends on the ratio of α / α A 156 and on the amount of β available. Since β inhibits the phosphorylation of calmodulin by CK2 α , the addition of CK2 α A 156 , in this case, increases calmodulin phosphorylation by the α and β combination. These results suggest that CK2 α A 156 may be a useful dominant‐negative mutant that can serve to explore the multiple functions of CK2 β .