S-palmitoylation regulates biogenesis of core glycosylated wild-type and F508del CFTR in a post-ER compartment

In this study, we used metabolic labeling to confirm that wild-type and F508del CFTR are palmitoylated, and show that blocking palmitoylation with the pharmacologic inhibitor 2-bromopalmitate (2-BP) decreases steady state levels of both wild-type and low temperature-corrected F508del CFTR, disrupts post-ER maturation, and reduces ion channel function at the cell surface. Protein acyl transferases (PATs) comprise a family of 23 gene products that contain a DHHC motif and mediate palmitoylation. Recombinant expression of specific PATs led to increased levels of CFTR protein and enhanced palmitoylation as judged by western blot and metabolic labeling. Specifically, we show that DHHC-7: 1) increases steady state levels of wild-type and F508del CFTR band B, 2) interacts preferentially with the band B glycoform, and 3) augments radiolabeling by 3H-palmitic acid. Interestingly, immunofluorescence revealed that DHHC-7 also sequesters the F508del protein to a post-ER (Golgi) compartment. Our findings point to the importance of palmitoylation during wild-type and F508del CFTR trafficking.

Source: BJ Cell - January 29, 2014 Category: Biochemistry Authors: M L. McClure, H Wen, J Fortenberry, J S. Hong, E J. Sorscher Tags: BJ ChemBio Source Type: research