Regulation of the CDK-related protein kinase PCTAIRE-1 and its possible role in neurite outgrowth in Neuro-2A cells.
PCTAIRE-1 is a CDK-related protein kinase found in terminally differentiated cells in brain and testis, and in many immortalised and transformed cell lines. Bacterially expressed PCTAIRE is completely inactive as a protein kinase, but is a very good substrate for protein kinase A (PKA), which phosphorylates a total of four sites in the N-terminus of PCTAIRE-1. Phosphorylation of one of these sites, Ser119, generates a 14-3-3 binding site, which is functional in vitro as well as in vivo. Mutation of another PKA site, Ser153, to an alanine residue generated an activated kinase in transfected mammalian cells. This activity was comparable to that of CDK5 activated by a bacterially expressed, truncated version of p35(nck), p21. Gel filtration analysis of a brain extract suggested that monomeric PCTAIRE-1 was the active species, implying that PCTAIRE-1 may not be a true CDK, in that it does not require a partner (cyclin-like) subunit for kinase activity. Finally, we found that various forms of PCTAIRE-1 transfected into neuroblastoma cell lines could either promote or inhibit neurite outgrowth, suggesting a potential role for the PCTAIRE-1 gene product in the control of neurite outgrowth.
Graeser
Ralph
R
ICRF Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK. r.graeser@proqinase.com
Gannon
Julian
J
Poon
Randy Y C
RY
Dubois
Thierry
T
Aitken
Alastair
A
Hunt
Tim
T
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D048429:Cell Size; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D016501:Neurites / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014020:Tissue Extracts / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D014020:Tissue Extracts; D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D018844:Cyclin-Dependent Kinases; C089463:PCTAIRE-1 protein kinase