Cloning, expression analysis, and functional characterization of PKL12, a member of a new subfamily of ser/thr kinases.
We report the cloning of the full-length cDNA of a new murine protein kinase, mPKL12. The sequence reveals a 305-amino-acid protein that contains the characteristic subdomains of the kinase superfamily and particular homology indicating a ser/thr specificity. We have also identified its human homologue gene (94% identical) and the putative homologue proteins from Saccharomyces cerevisiae and Arabidoposis thaliana. These four sequences appear to form a new subfamily of protein kinases, close in size to the theoretical minimal catalytic domain, therefore suggesting that they could be the catalytic unit of a more complex holoenzyme. Using Escherichia coli-purified protein, we have demonstrated that the mPKL12 enzyme possesses an intrinsic kinase activity, capable of phosphorylating enolase and also of promoting autophosphorylation, with a ser/thr specificity. Tissue expression analysis of mPKL12 showed that it is ubiquitously expressed, although at very low levels. RT-PCR analysis of several cell lines also supports this view, therefore suggesting that PKL12 may play a role in a very general cellular function, probably related with the secretory pathway.
Centro Nacional de Biotecnología, C.S.I.C., Campus de la Universidad Autónoma de Madrid, Cantoblanco, Madrid, E-28049, Spain.
J M
JM
Ligos
N
N
Gerwin
P
P
Fernández
J C
JC
Gutierrez-Ramos
A
A
Bernad
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D006412:Hematopoietic Stem Cells / Q000201:enzymology; D006801:Humans; D008099:Liver / Q000196:embryology / Q000201:enzymology; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D017385:Sequence Homology; D013379:Substrate Specificity
D012333:RNA, Messenger; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases