Abstract: TH-PO579
Palmitoylation of Polycystin 1 Occurs in the Carboxylterminus and May Regulate Polycystin 1 Localization and Expression Levels
Session Information
- Cystic Kidney Diseases - I
November 02, 2017 | Location: Hall H, Morial Convention Center
Abstract Time: 10:00 AM - 10:00 AM
Category: Genetic Diseases of the Kidney
- 801 Cystic Kidney Diseases
Authors
- Roy, Kasturi, Yale School of Medicine, New Haven, Connecticut, United States
- Stavola, Lindsey K., Yale School of Medicine, New Haven, Connecticut, United States
- Caplan, Michael J., Yale School of Medicine, New Haven, Connecticut, United States
- Marin, Ethan P., Yale School of Medicine, New Haven, Connecticut, United States
Background
Polycystin 1 (PC1) is a polytopic membrane protein that localizes to primary cilia. Genetic mutations that lead to reduced PC1 expression levels and/or trafficking to cilia cause cystic disease of the kidney and/or liver. Such mutations may occur in the PC1 gene (Pkd1), or in genes encoding endoplasmic reticuluum proteins involved in the maturation and trafficking of PC1. Cysteine palmitoylation is the post-translational attachment of the 16-carbon lipid palmitic acid to a cysteine sidechain, and is known the affect trafficking and stability of numerous proteins.
Methods
Palmitoylation of PC1 was assessed using a variety of biochemical approaches including incorporation of a clickable palmitate analog as well as acyl exchange methods. Effects of palmitoylation were gauged using chemical inhibitors of palmitoylation and depalmitoylation, coupled with immunofluorescence to assess PC1 localization and semi-quantitative Western blotting to assess PC1 expression levels.
Results
PC1 is palmitoylated on at least one cysteine in the ~140kDa carboxylterminal domain. Experiments using inhibitors of enzymatic palmitoylation and de-palmitoylation suggest that the modification facilitates trafficking of PC1 from the plasma membrane into the cilia membrane. Pharmacological inhibition of palmitoylation or depalmitoylation also alters PC1 expression levels in reciprocal directions
Conclusion
Collectively, these data identify palmitoylation as a novel post-translational modification on PC1 which may affect its trafficking and stability. Both factors are relevant to the development of cystic kidney and liver disease. Consequently, a more detailed understanding of the palmitoylation of PC1 may identify targets to pharmacologically manipulate its expression level and localization, and potentially reverse the effects of disease-causing mutations.
Funding
- Private Foundation Support