Identification of a novel phosphorylation site in c-jun directly targeted in vitro by protein kinase D
- Unit of Signal Transduction and Gastrointestinal Cancer, Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, UCLA-CURE, Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles (United States)
- Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute of Neuroscience and Human Behavior, Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles (United States)
Protein kinase D (PKD) phosphorylates the c-jun amino-terminal in vitro at site(s) distinct from JNK [C. Hurd, R.T. Waldron, E. Rozengurt, Protein kinase D complexes with c-jun N-terminal kinase via activation loop phosphorylation and phosphorylates the c-jun N-terminus, Oncogene 21 (2002) 2154-2160], but the sites have not been identified. Here, metabolic {sup 32}P-labeling of c-jun protein in COS-7 cells indicated that PKD phosphorylates c-jun in vivo at a site(s) between aa 43-93, a region containing important functional elements. On this basis, the PKD-mediated phosphorylation site(s) was further characterized in vitro using GST-c-jun fusion proteins. PKD did not incorporate phosphate into Ser63 and Ser73, the JNK sites in GST-c-jun(1-89). Rather, PKD and JNK could sequentially phosphorylate distinct site(s) simultaneously. By mass spectrometry of tryptic phosphopeptides, Ser58 interposed between the JNK-binding portion of the delta domain and the adjacent TAD1 was identified as a prominent site phosphorylated in vitro by PKD. These data were further supported by kinase reactions using truncations or point-mutations of GST-c-jun. Together, these data suggest that PKD-mediated phosphorylation modulates c-jun at the level of its N-terminal functional domains.
- OSTI ID:
- 20991322
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 356, Issue 2; Other Information: DOI: 10.1016/j.bbrc.2007.02.142; PII: S0006-291X(07)00389-0; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structure of Human Dual Specificity Protein Phosphatase 23, VHZ, Enzyme-Substrate/Product Complex
Fucoidan/FGF-2 induces angiogenesis through JNK- and p38-mediated activation of AKT/MMP-2 signalling