Autophosphorylation

Chimeric calcium/calmodulin dependent protein kinase (CCaMK) is characterized by the presence of a visinin-like Ca 2+ -binding domain unlike other known calmodulin-dependent kinases. Ca 2+ -Binding to the visinin-like domain leads to autophosphorylation and changes in the affinity for calmodulin [Sathyanarayanan P.V., Cremo C.R. & Poovaiah B.W. (2000)J. Biol. Chem. 275, 30417–30422]. Here, we report that the Ca 2+ -stimulated autophosphory-lation of CCaMK results in time-dependent loss of enzyme activity. ...

7p research12 29-04-2013 31 3   Download

Cryptochromes are blue-light photoreceptors sharing sequence similarity to photolyases, a class of flavoenzymes catalyzing repair ofUV-damagedDNAvia electron transfer mechanisms. Despite significant amino acid sequence simi-larity in both catalytic and cofactor-binding domains, cryptochromes lack DNA repair functions associated with photolyases, and the molecular mechanism involved in cryptochrome signaling remains obscure.

8p tumor12 20-04-2013 38 3   Download

The highly conserved, atypical RIO serine protein kinases are found in all organisms, from archaea to man. In yeast, the kinase activity of Rio2 is necessary for the final processing step of maturing the 18S ribosomal rRNA. We have previously shown that the Rio2 protein from Archaeo-globus fulgidus contains both a small kinase domain and an N-terminal winged helix domain.

0p awards 06-04-2013 41 3   Download

2-Cys peroxiredoxins (2-Cys Prx) are ubiquitous thiol-containing peroxidas-es that have been implicated in antioxidant defense and signal transduction. Although their biochemical features have been extensively studied, little is known about the mechanisms that link the redox activity and non-redox processes.

14p media19 06-03-2013 38 3   Download

DYRK1A is a dual-specificity protein kinase that autophosphorylates a conserved tyrosine residue in the activation loop but phosphorylates exoge-nous substrates only at serine or threonine residues. Tyrosine autophospho-rylation of DYRKs is a one-off event that takes place during translation and induces the activation of the kinase.

14p viettel02 20-02-2013 34 4   Download

Heme-regulated eukaryotic initiation factor 2a (eIF2a) kinase (HRI), functions in response to heme shortage in reticulocytes and aids in the maintenance of a heme:globin ratio of 1:1. Under normal conditions, heme binds to HRI and blocks its function.

11p cosis54 05-01-2013 28 4   Download