Title : N-Glycosylation
Regulates Pannexin 2 Localization but Is
Not Required for Interacting with
Pannexin 1
Abstract :
- Pannexins (Panx1 , 2, 3) are channel-forming glycoproteins expressed in mammalian tissues
- We previously reported that N-glycosylation acts as a regulator of the localization and intermixing of Panx1 and Panx3 , but its effects on Panx2 are currently unknown
- Panx1 and Panx2 intermixing can regulate channel properties, and both pannexins have been implicated in neuronal cell death after ischemia
- Our objectives were to validate the predicted N-glycosylation site of Panx2 and to study the effects of Panx2 glycosylation on localization and its capacity to interact with Panx1
- We used site-directed mutagenesis, enzymatic de-glycosylation, cell-surface biotinylation, co-immunoprecipitation, and confocal microscopy
- Our results showed that N86 is the only N-glycosylation site of Panx2
- Panx2 and the N86Q mutant are predominantly localized to the endoplasmic reticulum (ER) and cis-Golgi matrix with limited cell surface localization was seen only in the presence of Panx1
- The Panx2 N86Q mutant is glycosylation-deficient and tends to aggregate in the ER reducing its cell surface trafficking but it can still interact with Panx1
- Our study indicates that N-glycosylation may be important for folding and trafficking of Panx2
- We found that the un-glycosylated forms of Panx1 and 2 can readily interact, regulating their localization and potentially their channel function in cells where they are co-expressed