Mutagenesis of Thr-286 in monomeric Ca2+/calmodulin-dependent protein kinase II eliminates Ca2+/calmodulin-independent activity.
AUTOR(ES)
Waxham, M N
RESUMO
We have examined the role of Thr-286 autophosphorylation in the autoregulation of Ca2+/calmodulin-dependent protein kinase II. Using site-directed mutagenesis, we have substituted alanine or serine for Thr-286, or isoleucine for Arg-283, in the 50-kDa subunit of the kinase and expressed each protein in bacteria. Activation and autophosphorylation of all four enzymes were stringently dependent on Ca2+/calmodulin, indicating that neither Arg-283 nor Thr-286 is an absolute requirement for the pseudosubstrate inhibition of the enzyme. Autophosphorylation of the Ile-283 or Ala-286 enzyme generated little, if any, Ca2+/calmodulin-independent kinase activity, unlike the parent (Thr-286) or Ser-286 enzyme. The enzymes expressed in bacteria are predominantly monomeric, indicating that the generation of Ca2+/calmodulin-independent activity does not require the cooperative interactions of subunits normally present in the brain holoenzyme.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=53456Documentos Relacionados
- Antibody specific for the Thr-286-autophosphorylated alpha subunit of Ca2+/calmodulin-dependent protein kinase II.
- Ca2+/calmodulin-dependent protein kinase II: identification of threonine-286 as the autophosphorylation site in the alpha subunit associated with the generation of Ca2+-independent activity.
- Autophosphorylation reversibly regulates the Ca2+/calmodulin-dependence of Ca2+/calmodulin-dependent protein kinase II.
- Oestrogen confers cardioprotection by suppressing Ca2+/calmodulin-dependent protein kinase II
- Bidirectional control of phospholipase A2 activity by Ca2+/calmodulin-dependent protein kinase II, cAMP-dependent protein kinase, and casein kinase II.