Publication Date:
1992-05-22
Description:
Multifunctional calcium-calmodulin-dependent protein kinase (CaM kinase) transduces transient elevations in intracellular calcium into changes in the phosphorylation state and activity of target proteins. By fluorescence emission anisotropy, the affinity of CaM kinase for dansylated calmodulin was measured and found to increase 1000 times after autophosphorylation of the threonine at position 286 of the protein. Autophosphorylation markedly slowed the release of bound calcium-calmodulin; the release time increased from less than a second to several hundred seconds. In essence, calmodulin is trapped by autophosphorylation. The shift in affinity does not occur in a site-directed mutant in which threonine at position 286 has been replaced by a non-phosphorylatable amino acid. These experiments demonstrate the existence of a new state in which calmodulin is bound to CaM kinase even though the concentration of calcium is basal. Calmodulin trapping provides for molecular potentiation of calcium transients and may enable detection of their frequency.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meyer, T -- Hanson, P I -- Stryer, L -- Schulman, H -- GM 40600/GM/NIGMS NIH HHS/ -- GM24032/GM/NIGMS NIH HHS/ -- MH45324/MH/NIMH NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1992 May 22;256(5060):1199-202.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, Stanford University School of Medicine, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1317063" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Base Sequence
;
Binding, Competitive
;
Calcium/pharmacology
;
Calcium-Calmodulin-Dependent Protein Kinases
;
Calmodulin/*metabolism
;
Cell Line
;
Egtazic Acid/pharmacology
;
Kinetics
;
Molecular Sequence Data
;
Mutagenesis, Site-Directed
;
Phosphorylation
;
Protein Binding
;
Protein Kinases/genetics/*metabolism
;
Recombinant Proteins/metabolism
;
Spectrometry, Fluorescence
;
Threonine
;
Time Factors
;
Transfection
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
