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In Vivo and In Vitro Characterization of the Sequence Requirement for Oligomer Formation of Ca 2+ /Calmodulin‐Dependent Protein Kinase IIα
Author(s) -
Shen Kang,
Meyer Tobias
Publication year - 1998
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1998.70010096.x
Subject(s) - autophosphorylation , calmodulin , oligomer , biochemistry , protein kinase a , serine , protein subunit , biology , kinase , camk , microbiology and biotechnology , enzyme , chemistry , gene , organic chemistry
Ca 2+ /calmodulin‐dependent protein kinase II (CaMK II) is a multifunctional serine/threonine protein kinase that regulates ion channels, metabolic enzymes, cytoskeletal proteins, and possibly transcription factors. CaMK II holoenzymes have been shown to be large oligomers built from eight or more subunits. The oligomeric structure of CaMK II is required for a critical trans‐autophosphorylation step by which each subunit traps bound calmodulin and renders the enzyme partially active in the absence of Ca 2+ /calmodulin. Here we define a minimal C‐terminal domain of αCaMK II that is necessary and sufficient for oligomerization. The oligomeric structure of αCaMK II deletion mutants was investigated in vitro by gel filtration chromatography and in living cells by measuring nuclear exclusion and diffusion coefficients of green fluorescent protein‐tagged mutants. These studies showed that a C‐terminal region of αCaMK II of 135 amino acids is sufficient for oligomer formation. Oligomer formation was abolished by further C‐terminal and N‐terminal deletions, indicating that the same region is not only sufficient but also necessary for oligomerization. Thus, an oligomerization domain of only 15 kDa is sufficient to build the circular structure of CaMK II holoenzyme.