title: Exocyst Sec10 protects renal tubule cells from injury by EGFR/MAPK activation and effects on endocytosis.
abstract: Acute kidney injury is common and has a high mortality rate, and no effective treatment exists other than supportive care. Using cell culture models, we previously demonstrated that exocyst Sec10 overexpression reduced damage to renal tubule cells and speeded recovery and that the protective effect was mediated by higher basal levels of mitogen-activated protein kinase (MAPK) signaling. The exocyst, a highly-conserved eight-protein complex, is known for regulating protein trafficking. Here we show that the exocyst biochemically interacts with the epidermal growth factor receptor (EGFR), which is upstream of MAPK, and Sec10-overexpressing cells express greater levels of phosphorylated (active) ERK, the final step in the MAPK pathway, in response to EGF stimulation. EGFR endocytosis, which has been linked to activation of the MAPK pathway, increases in Sec10-overexpressing cells, and gefitinib, a specific EGFR inhibitor, and Dynasore, a dynamin inhibitor, both reduce EGFR endocytosis. In turn, inhibition of the MAPK pathway reduces ligand-mediated EGFR endocytosis, suggesting a potential feedback of elevated ERK activity on EGFR endocytosis. Gefitinib also decreases MAPK signaling in Sec10-overexpressing cells to levels seen in control cells and, demonstrating a causal role for EGFR, reverses the protective effect of Sec10 overexpression following cell injury in vitro. Finally, using an in vivo zebrafish model of acute kidney injury, morpholino-induced knockdown of sec10 increases renal tubule cell susceptibility to injury. Taken together, these results suggest that the exocyst, acting through EGFR, endocytosis, and the MAPK pathway is a candidate therapeutic target for acute kidney injury.
authors.affiliation: Departments of Anatomy, Biochemistry, and Physiology, University of Hawaii at Manoa, Honolulu, Hawaii;
authors.forename: Ben
authors.initials: B
authors.lastname: Fogelgren
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston, South Carolina;
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zuo
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania;
authors.forename: Janine M
authors.initials: JM
authors.lastname: Buonato
authors.affiliation: Department of Pathology, Harvard Medical School, Boston, Massachusetts;
authors.forename: Aleksandr
authors.initials: A
authors.lastname: Vasilyev
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston, South Carolina;
authors.forename: Jeong-In
authors.initials: JI
authors.lastname: Baek
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston, South Carolina;
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania;
authors.forename: Maria F
authors.initials: MF
authors.lastname: Chacon-Heszele
authors.affiliation: Department of Pathology, Harvard Medical School, Boston, Massachusetts;
authors.forename: Aurélien
authors.initials: A
authors.lastname: Palmyre
authors.affiliation: Departments of Anatomy, Biochemistry, and Physiology, University of Hawaii at Manoa, Honolulu, Hawaii;
authors.forename: Noemi
authors.initials: N
authors.lastname: Polgar
authors.affiliation: Departments of Medicine and Genetics, Harvard Medical School, Boston, Massachusetts;
authors.forename: Iain
authors.initials: I
authors.lastname: Drummond
authors.affiliation: Department of Anatomy and BK21 Plus, Kyungpook National University School of Medicine, Junggu, Daegu, Republic of Korea; and.
authors.forename: Kwon Moo
authors.initials: KM
authors.lastname: Park
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania;
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Lazzara
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston, South Carolina; Department of Medicine, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina Lipschut@musc.edu.
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Lipschutz
mesh_terms: D058186:Acute Kidney Injury / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D000818:Animals; D030801:Animals, Genetically Modified; D004195:Disease Models, Animal; D004285:Dogs; D004705:Endocytosis / Q000187:drug effects; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007684:Kidney Tubules / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D061985:Madin Darby Canine Kidney Cells; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D018384:Oxidative Stress; D010766:Phosphorylation; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C419575:EXOC5 protein, human; D047428:Protein Kinase Inhibitors; D033921:Vesicular Transport Proteins; D029961:Zebrafish Proteins; C485184:enhanced green fluorescent protein; C560185:exoc5 protein, zebrafish; D049452:Green Fluorescent Proteins; C512478:EGFR protein, human; D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases
keywords: AKI; EGFR; MAPK; exocyst