Polycystin-1 Interacting Protein-1 (CU062) Interacts with the Ectodomain of Polycystin-1 (PC1)
Wendy A. Lea,
Thomas Winklhofer,
Lesya Zelenchuk,
Madhulika Sharma,
Jessica Rossol-Allison,
Timothy A. Fields,
Gail Reif,
James P. Calvet,
Jason L. Bakeberg,
Darren P. Wallace,
Christopher J. Ward
Affiliations
Wendy A. Lea
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
Thomas Winklhofer
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
Lesya Zelenchuk
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
Madhulika Sharma
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
Jessica Rossol-Allison
Promega Corporation, 2800 Woods Hollow Road, Madison, WI 53711, USA
Timothy A. Fields
Department of Pathology & Laboratory Medicine, University of Kansas Medical Center, 3901 Rainbow Blvd., Mail Stop 3062, Kansas City, KS 66160, USA
Gail Reif
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
James P. Calvet
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
Jason L. Bakeberg
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
Darren P. Wallace
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
Christopher J. Ward
Department of Nephrology and Hypertension, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, 3901 Rainbow Blvd., Mail Stop 3018, KS 66160, USA
The PKD1 gene, encoding protein polycystin-1 (PC1), is responsible for 85% of cases of autosomal dominant polycystic kidney disease (ADPKD). PC1 has been shown to be present in urinary exosome−like vesicles (PKD−ELVs) and lowered in individuals with germline PKD1 mutations. A label−free mass spectrometry comparison of urinary PKD−ELVs from normal individuals and those with PKD1 mutations showed that several proteins were reduced to a degree that matched the decrease observed in PC1 levels. Some of these proteins, such as polycystin-2 (PC2), may be present in a higher-order multi-protein assembly with PC1—the polycystin complex (PCC). CU062 (Q9NYP8) is decreased in ADPKD PKD−ELVs and, thus, is a candidate PCC component. CU062 is a small glycoprotein with a signal peptide but no transmembrane domain and can oligomerize with itself and interact with PC1. We investigated the localization of CU062 together with PC1 and PC2 using immunofluorescence (IF). In nonconfluent cells, all three proteins were localized in close proximity to focal adhesions (FAs), retraction fibers (RFs), and RF-associated extracellular vesicles (migrasomes). In confluent cells, primary cilia had PC1/PC2/CU062 + extracellular vesicles adherent to their plasma membrane. In cells exposed to mitochondrion-decoupling agents, we detected the development of novel PC1/CU062 + ring-like structures that entrained swollen mitochondria. In contact-inhibited cells under mitochondrial stress, PC1, PC2, and CU062 were observed on large, apically budding extracellular vesicles, where the proteins formed a reticular network on the membrane. CU062 interacts with PC1 and may have a role in the identification of senescent mitochondria and their extrusion in extracellular vesicles.