title: Store-operated Ca2+ entry (SOCE) induced by protease-activated receptor-1 mediates STIM1 protein phosphorylation to inhibit SOCE in endothelial cells through AMP-activated protein kinase and p38β mitogen-activated protein kinase.
abstract: The Ca(2+) sensor STIM1 is crucial for activation of store-operated Ca(2+) entry (SOCE) through transient receptor potential canonical and Orai channels. STIM1 phosphorylation serves as an "off switch" for SOCE. However, the signaling pathway for STIM1 phosphorylation is unknown. Here, we show that SOCE activates AMP-activated protein kinase (AMPK); its effector p38β mitogen-activated protein kinase (p38β MAPK) phosphorylates STIM1, thus inhibiting SOCE in human lung microvascular endothelial cells. Activation of AMPK using 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) resulted in STIM1 phosphorylation on serine residues and prevented protease-activated receptor-1 (PAR-1)-induced Ca(2+) entry. Furthermore, AICAR pretreatment blocked PAR-1-induced increase in the permeability of mouse lung microvessels. Activation of SOCE with thrombin caused phosphorylation of isoform α1 but not α2 of the AMPK catalytic subunit. Moreover, knockdown of AMPKα1 augmented SOCE induced by thrombin. Interestingly, SB203580, a selective inhibitor of p38 MAPK, blocked STIM1 phosphorylation and led to sustained STIM1-puncta formation and Ca(2+) entry. Of the three p38 MAPK isoforms expressed in endothelial cells, p38β knockdown prevented PAR-1-mediated STIM1 phosphorylation and potentiated SOCE. In addition, inhibition of the SOCE downstream target CaM kinase kinase β (CaMKKβ) or knockdown of AMPKα1 suppressed PAR-1-mediated phosphorylation of p38β and hence STIM1. Thus, our findings demonstrate that SOCE activates CaMKKβ-AMPKα1-p38β MAPK signaling to phosphorylate STIM1, thereby suppressing endothelial SOCE and permeability responses.
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612-7343.
authors.forename: Premanand C
authors.initials: PC
authors.lastname: Sundivakkam
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612-7343.
authors.forename: Viswanathan
authors.initials: V
authors.lastname: Natarajan
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612-7343.
authors.forename: Asrar B
authors.initials: AB
authors.lastname: Malik
authors.affiliation: Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612-7343. Electronic address: tiruc@uic.edu.
authors.forename: Chinnaswamy
authors.initials: C
authors.lastname: Tiruppathi
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000235:genetics / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D008168:Lung / Q000098:blood supply / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D048290:Mitogen-Activated Protein Kinase 11 / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D044463:Receptor, PAR-1 / Q000235:genetics / Q000378:metabolism*; D012265:Ribonucleotides / Q000494:pharmacology; D000071737:Stromal Interaction Molecule 1
chemical_list: D015220:Calcium Channels; D007004:Hypoglycemic Agents; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D044463:Receptor, PAR-1; D012265:Ribonucleotides; C103530:STIM1 protein, human; C100757:Stim1 protein, mouse; D000071737:Stromal Interaction Molecule 1; D000620:Aminoimidazole Carboxamide; C548179:Prkaa1 protein, mouse; C517698:CAMKK2 protein, human; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; C517700:Camkk2 protein, mouse; D048290:Mitogen-Activated Protein Kinase 11; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide; D002118:Calcium
keywords: AMP-activated Kinase (AMPK); Calcium Channels; Endothelial Dysfunction; Phosphorylation; Protease-activated Receptor-1; Store-operated Calcium Entry; Stromal Interaction Molecule-1; Thrombin; Vascular Permeability; p38 MAPK