title: The Golgi apparatus regulates cGMP-dependent protein kinase I compartmentation and proteolysis.
abstract: cGMP-dependent protein kinase I (PKGI) is an important effector of cGMP signaling that regulates vascular smooth muscle cell (SMC) phenotype and proliferation. PKGI has been detected in the perinuclear region of cells, and recent data indicate that proprotein convertases (PCs) typically resident in the Golgi apparatus (GA) can stimulate PKGI proteolysis and generate a kinase fragment that localizes to the nucleus and regulates gene expression. However, the role of the endomembrane system in PKGI compartmentation and processing is unknown. Here, we demonstrate that PKGI colocalizes with endoplasmic reticulum (ER), ER-Golgi intermediate compartment, GA cisterna, and trans-Golgi network proteins in pulmonary artery SMC and cell lines. Moreover, PKGI localizes with furin, a trans-Golgi network-resident PC known to cleave PKGI. ER protein transport influences PKGI localization because overexpression of a constitutively inactive Sar1 transgene caused PKGI retention in the ER. Additionally, PKGI appears to reside within the GA because PKGI immunoreactivity was determined to be resistant to cytosolic proteinase K treatment in live cells. The GA appears to play a role in PKGI proteolysis because overexpression of inositol 1,4,5-trisphosphate receptor-associated cGMP kinase substrate, not only tethered heterologous PKGI-β to the ER and decreased its localization to the GA, but also diminished PKGI proteolysis and nuclear translocation. Also, inhibiting intra-GA protein transport with monensin was observed to decrease PKGI cleavage. These studies detail a role for the endomembrane system in regulating PKGI compartmentation and proteolysis. Moreover, they support the investigation of mechanisms regulating PKGI-dependent nuclear cGMP signaling in the pulmonary vasculature with Golgi dysfunction.
authors: Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts;
authors: Shin
authors: S
authors: Kato
authors: Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts;
authors: Jingsi
authors: J
authors: Chen
authors: Applied Video Research, Medford, Massachusetts.
authors: Katherine H
authors: KH
authors: Cornog
authors: Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts;
authors: Huili
authors: H
authors: Zhang
authors: Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts; Departments of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School, Cambridge, Massachusetts; roberts@cvrc.mgh.harvard.edu.
authors: Jesse D
authors: JD
authors: Roberts
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D003412:Cricetulus; D006152:Cyclic GMP / Q000378:metabolism*; D062965:Cyclic GMP-Dependent Protein Kinase Type I / Q000235:genetics* / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D045683:Furin / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D008985:Monensin / Q000494:pharmacology; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D059748:Proteolysis / Q000187:drug effects; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D011993:Recombinant Fusion Proteins; D008985:Monensin; D062965:Cyclic GMP-Dependent Protein Kinase Type I; D045683:Furin; C493083:SAR1A protein, human; D020559:Monomeric GTP-Binding Proteins; D006152:Cyclic GMP
keywords: Golgi apparatus; cGMP signaling; cGMP-dependent protein kinase I