Association of diacylglycerol kinase zeta with protein kinase C alpha: spatial regulation of diacylglycerol signaling.
Activation of PKC depends on the availability of DAG, a signaling lipid that is tightly and dynamically regulated. DAG kinase (DGK) terminates DAG signaling by converting it to phosphatidic acid. Here, we demonstrate that DGKzeta inhibits PKCalpha activity and that DGK activity is required for this inhibition. We also show that DGKzeta directly interacts with PKCalpha in a signaling complex and that the binding site in DGKzeta is located within the catalytic domain. Because PKCalpha can phosphorylate the myristoylated alanine-rich C-kinase substrate (MARCKS) motif of DGKzeta, we tested whether this modification could affect their interaction. Phosphorylation of this motif significantly attenuated coimmunoprecipitation of DGKzeta and PKCalpha and abolished their colocalization in cells, indicating that it negatively regulates binding. Expression of a phosphorylation-mimicking DGKzeta mutant that was unable to bind PKCalpha did not inhibit PKCalpha activity. Together, our results suggest that DGKzeta spatially regulates PKCalpha activity by attenuating local accumulation of signaling DAG. This regulation is impaired by PKCalpha-mediated DGKzeta phosphorylation.
Luo
Bai
B
The Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112, USA. matt.topham@hci.utah.edu
Prescott
Stephen M
SM
Topham
Matthew K
MK
D016475:3T3 Cells; D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D002135:Calcium-Binding Proteins; D020134:Catalytic Domain / Q000502:physiology; D019852:Diacylglycerol Kinase / Q000235:genetics / Q000378:metabolism*; D004075:Diglycerides / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000201:enzymology*; D005959:Glucosidases; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051379:Mice; D009154:Mutation / Q000502:physiology; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding / Q000502:physiology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*
D002135:Calcium-Binding Proteins; D004075:Diglycerides; D047908:Intracellular Signaling Peptides and Proteins; C000619710:MARCKS protein, human; C000619711:Marcks protein, mouse; C000619712:Marcks protein, rat; D008565:Membrane Proteins; D010750:Phosphoproteins; C512949:Prkcsh protein, mouse; C512948:Prkcsh protein, rat; D020033:Protein Isoforms; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D019852:Diacylglycerol Kinase; C496628:PRKCA protein, human; C496630:Prkca protein, mouse; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D005959:Glucosidases; C070368:PRKCSH protein, human