Trafficking dynamics of glycosylated pannexin 1 proteins.
Pannexins are mammalian orthologs of innexins and have a predicted topological folding pattern similar to that of connexins, except they are glycosylated. Rat pannexin 1 is glycosylated at N254 and this residue is important for plasma membrane targeting. Here we demonstrate that cell surface expression levels of the rat pannexin 1 N254Q mutant are rescued by coexpression with the wild-type protein. In paired Xenopus oocytes, the functional effect of this rescue is inconsequential; however, cell surface deglycosylation by PNGase F significantly enhanced functional gap junction formation. In mammalian cells, wild-type oligomers traffic at a slower rate than Myc-or tetracysteine domain-tagged versions, a behavior opposite to that of tagged connexins. The temporal differences of Panx1 trafficking correlate with spatial differences of intracellular localizations induced by Golgi blockage by Brefeldin-A or glycosylation prevention by tunicamycin. Therefore, Panx1 has kinetics and dynamics that make it unique to serve distinct functions separate from connexin-based channels.
Boassa
Daniela
D
National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, University of California, San Diego, La Jolla, California 92093-0608, USA. dboassa@gmail.com
Qiu
Feng
F
Dahl
Gerhard
G
Sosinsky
Gina
G
D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D017630:Connexins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D005500:Follow-Up Studies; D017629:Gap Junctions / Q000737:chemistry / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007700:Kinetics; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D051381:Rats
D017630:Connexins; D009419:Nerve Tissue Proteins; C479936:pannexin 1, rat