Phosphorylation at Ser244 by CK1 determines nuclear localization and substrate targeting of PKD2.
Protein kinase D2 (PKD2), a member of the PKD family of serine/threonine kinases, is localized in various subcellular compartments including the nucleus where the kinase accumulates upon activation of G-protein-coupled receptors. We define three critical post-translational modifications required for nuclear accumulation of PKD2 in response to activation of the CCK2 receptor (CCK2R): phosphorylation at Ser706 and Ser710 within the activation loop by PKC eta leading to catalytic activity and phosphorylation at Ser244 within the zinc-finger domain, which is crucial for blocking nuclear export of active PKD2 by preventing its interaction with the Crm-1 export machinery. We identify CK1delta and epsilon as upstream activated kinases by CCK2R that phosphorylate PKD2 at Ser244. Moreover, nuclear accumulation of active PKD2 is a prerequisite for efficient phosphorylation of its nuclear substrate, HDAC7. Only nuclear, active PKD2 mediates CCK2R-induced HDAC7 phosphorylation and Nur77 expression. Thus, we define a novel, compartment-specific signal transduction pathway downstream of CCK2R that phosphorylates PKD2 at three specific sites, results in nuclear accumulation of the active kinase and culminates in efficient phosphorylation of nuclear PKD2 substrates in human gastric cancer cells.
von Blume
J
J
Department of Internal Medicine I, University of Ulm, Ulm, Germany.
Knippschild
Uwe
U
Dequiedt
Franck
F
Giamas
Georgios
G
Beck
Alexander
A
Auer
Alexandra
A
Van Lint
Johan
J
Adler
Guido
G
Seufferlein
Thomas
T
D000818:Animals; D019556:COS Cells; D048149:Casein Kinase 1 epsilon / Q000378:metabolism*; D048148:Casein Kinase Idelta / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000378:metabolism; D005755:Gastrins / Q000494:pharmacology; D006367:HeLa Cells; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D000091283:Protein Kinase D2; D011494:Protein Kinases / Q000378:metabolism*; D043887:Receptor, Cholecystokinin B / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D011987:Receptors, Steroid / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
D004268:DNA-Binding Proteins; D005755:Gastrins; C539821:NR4A1 protein, human; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D000091283:Protein Kinase D2; D043887:Receptor, Cholecystokinin B; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014157:Transcription Factors; D012694:Serine; D011494:Protein Kinases; D048149:Casein Kinase 1 epsilon; D048148:Casein Kinase Idelta; D011493:Protein Kinase C; C543273:HDAC7 protein, human; D006655:Histone Deacetylases