Abstract: PO1507
Cleavage Fragments of Polycystin 1 Respond to Oxidative Stress and Alter Mitochondrial Dynamics and Function
Session Information
- Cystic Kidney Diseases: Mechanisms, Genetics, and Treatment
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1001 Genetic Diseases of the Kidneys: Cystic
Authors
- Pellegrini, Hannah, University of California Santa Barbara, Santa Barbara, California, United States
- Sharpe, Elizabeth H., University of California Santa Barbara, Santa Barbara, California, United States
- Weimbs, Thomas, University of California Santa Barbara, Santa Barbara, California, United States
Background
The PKD1 gene, which is mutated in ADPKD, encodes for the PC1 transmembrane protein containing a cytoplasmic C-terminal tail that undergoes cleavage at multiple sites. Two of these C-terminal fragments, a ~30 kDa fragment (p30), and a ~15 kDa fragment (p15) corresponding to the entire soluble C-terminal tail and the extreme end respectively, are overexpressed in patient kidneys.
Metabolic reprogramming is a hallmark of ADPKD. We demonstrate that the C-terminal fragments of PC1 respond to oxidative stress and contribute to metabolic reprogramming by altering mitochondrial dynamics.
Methods
MDCK and OK cell lines were generated stably expressing myc-tagged p30 or p15 under a doxycycline-inducible promoter
Protein levels of p30 were determined by western blot and localization by immunocytochemistry. Mitochondrial morphology was classified performing immunocytochemistry combined with image analysis. Fatty acid oxidation was assessed performing OilRedO staining and quantified by measuring the number of lipid droplets
Results
p30 normally undergoes rapid degradation and is stabilized in response to oxidative stress. Following glutamine starvation, p30 targets mitochondria and results in fragmentation. p15 does not undergo degradation and constitutively targets to the mitochondria where it induces mitochondrial fragmentation. Further, expressing p15 results in accumulation of lipid droplets indicative of impaired mitochondrial β-oxidation.
Conclusion
Our data unmasks p30 as a sensor of metabolic stress. We speculate that p30 stabilization and subsequent p15 cleavage are involved in metabolic reprogramming in ADPKD by altering mitochondrial morphology and function. Elucidating the exact underlying mechanisms is of major importance to understanding disease progression in ADPKD.