Characterization of a new family of protein kinases from Arabidopsis containing phosphoinositide 3/4-kinase and ubiquitin-like domains.
At least two of the genes predicted to encode type II PI4K (phosphoinositide 4-kinase) in Arabidopsis thaliana (thale cress), namely AtPI4Kgamma4 and AtPI4Kgamma7, encode enzymes with catalytic properties similar to those of members of the PIKK (phosphoinositide kinase-related kinase) family. AtPI4Kgamma4 and AtPI4Kgamma7 undergo autophosphorylation and phosphorylate serine/threonine residues of protein substrates, but have no detectable lipid kinase activity. AtPI4Kgamma4 and AtPI4Kgamma7 are members of a subset of five putative AtPI4Ks that contain N-terminal UBL (ubiquitin-like) domains. In vitro analysis of AtPI4Kgamma4 indicates that it interacts directly with, and phosphorylates, two proteins involved in the ubiquitin-proteasome system, namely UFD1 (ubiquitin fusion degradation 1) and RPN10 (regulatory particle non-ATPase 10). On the basis of the present results, we propose that AtPI4Kgamma4 and AtPI4Kgamma7 should be designated UbDKgamma4 and UbDKgamma7 (ubiquitin-like domain kinases gamma4 and gamma7). These UBL-domain-containing AtPI4Ks correspond to a new PIKK subfamily of protein kinases. Furthermore, UFD1 and RPN10 phosphorylation represents an additional mechanism by which their function can be regulated.
Galvão
Rafaelo M
RM
Department of Plant Biology, North Carolina State University, Raleigh, NC 27695, USA.
Kota
Uma
U
Soderblom
Erik J
EJ
Goshe
Michael B
MB
Boss
Wendy F
WF
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry*; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism; D002384:Catalysis; D058543:Class Ia Phosphatidylinositol 3-Kinase; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases / Q000737:chemistry* / Q000378:metabolism*; D010766:Phosphorylation; D010802:Phylogeny; D011494:Protein Kinases / Q000737:chemistry* / Q000145:classification*; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D025801:Ubiquitin / Q000737:chemistry* / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D029681:Arabidopsis Proteins; D018076:DNA, Complementary; C475163:RPN10 protein, Arabidopsis; D011994:Recombinant Proteins; D025801:Ubiquitin; D011494:Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D058543:Class Ia Phosphatidylinositol 3-Kinase