An inactive mutant of the α subunit of protein kinase CK2 that traps the regulatory CK2β subunit

FEBS Letters

Antonelli, Marcelo²  Allende, Jorge E²  Cosmelli, Diego²  Allende, Catherine C¹ 

[1]Departamento de Biologı́a, Facultad de Ciencias, Universidad de Chile, Casilla 70086, Santiago 7, Chile

[2]Programa de Biologı́a Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70086, Santiago 7, Chile

关键词: Protein kinase CK2;    Casein kinase II;    CK2α subunit mutant;    CK2β subunit;    Dominant-negative mutant;    CK2α and CK2β;    the α and β subunits of protein kinase CK2;    CK2αA156;    mutant of recombinant CK2α in which D156 is changed to A;   

DOI  :  10.1016/S0014-5793(97)00625-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 (CK2αA¹⁵⁶) resulted in an inactive enzyme. The CK2αA¹⁵⁶ mutant, however, binds the regulatory subunit as measured by retention of β on a nickel chelating column mediated by (His)₆-tagged CK2αA¹⁵⁶. Addition of CK2αA¹⁵⁶ 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). CK2αA¹⁵⁶ 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/αA¹⁵⁶ and on the amount of β available. Since β inhibits the phosphorylation of calmodulin by CK2α, the addition of CK2αA¹⁵⁶, in this case, increases calmodulin phosphorylation by the α and β combination. These results suggest that CK2αA¹⁵⁶ may be a useful dominant-negative mutant that can serve to explore the multiple functions of CK2β.

【 授权许可】

Unknown