Abstract
Desmoplakin (DP) is an obligate component of desmosomes, intercellular adhesive junctions that maintain the integrity of the epidermis and myocardium. Mutations in DP can cause cardiac and cutaneous disease, including arrhythmogenic cardiomyopathy (ACM), an inherited disorder that frequently results in deadly arrhythmias. Conduction defects in ACM are linked to the remodeling and functional interference with Cx43-based gap junctions that electrically and chemically couple cells. How DP loss impairs gap junctions is poorly understood. We show that DP prevents lysosomal-mediated degradation of Cx43. DP loss triggered robust activation of ERK1/2-MAPK and increased phosphorylation of S279/282 of Cx43, which signals clathrin-mediated internalization and subsequent lysosomal degradation of Cx43. RNA sequencing revealed Ras-GTPases as candidates for the aberrant activation of ERK1/2 upon loss of DP. Using a novel Ras inhibitor, Ras/Rap1-specific peptidase (RRSP), or K-Ras knockdown, we demonstrate restoration of Cx43 in DP-deficient cardiomyocytes. Collectively, our results reveal a novel mechanism for the regulation of the Cx43 life cycle by DP in cardiocutaneous models.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3219-3235 |
| Number of pages | 17 |
| Journal | Journal of Cell Biology |
| Volume | 217 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 1 2018 |
Funding
We thank Jeffrey Saffitz (Beth Israel Deaconess Medical Center) for providing ACM patient cardiac samples. We thank Gillian Fitz, Lisa Godsel, and Jennifer Koetsier for their experimental/technical assistance. We also thank Jong Kook Park and Robert Lavker for their guidance in carrying out LY dye transfer assays. Sequencing services were performed at the Northwestern University Genomics Core Facility. Tissue sectioning and lentiviral particle production was performed at the Northwestern University Skin Disease Research Center (supported in part by P30AR057216). We thank Jeffrey Saffitz (Beth Israel Deaconess Medical Center) for providing ACM patient cardiac samples. We thank Gillian Fitz, Lisa Godsel, and Jennifer Koetsier for their experimental/technical assistance. We also thank Jong Kook Park and Robert Lavker for their guidance in carrying out LY dye transfer assays. Sequencing services were performed at the Northwestern University Genomics Core Facility. Tissue sectioning and lentiviral particle production was performed at the Northwestern University Skin Disease Research Center (supported in part by P30AR057216). This work was supported by NIH grant R37AR43380 and the J.L. Mayberry Endowment (to K.J. Green). P.D. Lampe is supported by NIH grant GM55632. F. Sheikh is supported by grants from NIH/National Heart, Lung, and Blood Institute (R01 HL09780-06) and the Tobacco-Related Disease Research Program (24RT-022). K.J.F. Satchell is supported by a Translational Research Grant from Robert H. Lurie Comprehensive Cancer Center and the Northwestern Medicine Catalyst Fund. S. Polo is supported by the Associazione Italiana per la Ricerca sul Cancro (IG11627) and Worldwide Cancer Research (11-0051). C.Y. Kam was supported by a American Heart Association predoctoral fellowship (15PRE25560138). The authors declare no competing financial interests. Author contributions: C.Y. Kam and K.J. Green designed the study, analyzed the data, and wrote the manuscript. C.Y. Kam performed most of the experiments. A.D. Dubash assisted with the generation of reagents and analysis of data. P. Lampe generated the phosphospecific Cx43 antibodies used for this study. F. Sheikh generated the DPcKO mouse model. K.J.F. Satchell generated RRSP and provided technical assistance for its use. S. Polo and E. Magistrati provided reagents and participated in the preparation of the manuscript. All authors provided critical feedback on the manuscript. This work was supported by NIH grant R37AR43380 and the J.L. Mayberry Endowment (to K.J. Green). P.D. Lampe is supported by NIH grant GM55632. F. Sheikh is supported by grants from NIH/National Heart, Lung, and Blood Institute (R01 HL09780-06) and the Tobacco-Related Disease Research Program (24RT-022). K.J.F. Satchell is supported by a Translational Research Grant from Robert H. Lurie Comprehensive Cancer Center and the Northwestern Medicine Catalyst Fund. S. Polo is supported by the Associazione Italiana per la Ricerca sul Cancro (IG11627) and Worldwide Cancer Research (11-0051). C.Y. Kam was supported by a American Heart Association predoctoral fellowship (15PRE25560138). The authors declare no competing financial interests.
ASJC Scopus subject areas
- Cell Biology