Protein kinase C-associated kinase (PKK), a novel membrane-associated, ankyrin repeat-containing protein kinase.
A novel murine membrane-associated protein kinase, PKK (protein kinase C-associated kinase), was cloned on the basis of its physical association with protein kinase Cbeta (PKCbeta). The regulated expression of PKK in mouse embryos is consistent with a role for this kinase in early embryogenesis. The human homolog of PKK has over 90% identity to its murine counterpart, has been localized to chromosome 21q22.3, and is identical to the PKCdelta-interacting kinase, DIK (Bahr, C., Rohwer, A., Stempka, L., Rincke, G., Marks, F., and Gschwendt, M. (2000) J. Biol. Chem. 275, 36350-36357). PKK comprises an N-terminal kinase domain and a C-terminal region containing 11 ankyrin repeats. PKK exhibits protein kinase activity in vitro and associates with cellular membranes. PKK exists in three discernible forms at steady state: an underphosphorylated form of 100 kDa; a soluble, cytosolic, phosphorylated form of 110 kDa; and a phosphorylated, detergent-insoluble form of 112 kDa. PKK is initially synthesized as an underphosphorylated soluble 100-kDa protein that is quantitatively converted to a detergent-soluble 110-kDa form. This conversion requires an active catalytic domain. Although PKK physically associates with PKCbeta, it does not phosphorylate this PKC isoform. However, PKK itself may be phosphorylated by PKCbeta. PKK represents a developmentally regulated protein kinase that can associate with membranes. The functional significance of its association with PKCbeta remains to be ascertained.
Chen
L
L
Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
Haider
K
K
Ponda
M
M
Cariappa
A
A
Rowitch
D
D
Pillai
S
S
D000595:Amino Acid Sequence; D000818:Animals; D017089:Ankyrin Repeat; D001483:Base Sequence; D019556:COS Cells; D002462:Cell Membrane / Q000201:enzymology; D002522:Chlorocebus aethiops; D002874:Chromosome Mapping; D002891:Chromosomes, Human, Pair 21; D003600:Cytosol / Q000201:enzymology; D005314:Embryonic and Fetal Development; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection
D007527:Isoenzymes; D011994:Recombinant Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C430884:Ripk4 protein, mouse; D011493:Protein Kinase C; D064546:Protein Kinase C beta