PUBLICATION

Distinct roles for luminal acidification in apical protein sorting and trafficking in zebrafish

Authors
Levic, D.S., Ryan, S., Marjoram, L., Honeycutt, J., Bagwell, J., Bagnat, M.
ID
ZDB-PUB-200426-13
Date
2020
Source
The Journal of cell biology   219(4): (Journal)
Registered Authors
Bagnat, Michel
Keywords
none
MeSH Terms
  • Animals
  • Hydrogen-Ion Concentration
  • Membrane Proteins/genetics
  • Membrane Proteins/metabolism*
  • Mutation
  • Phenobarbital/chemistry
  • Phenobarbital/metabolism*
  • Protein Transport
  • Proton-Translocating ATPases/genetics
  • Proton-Translocating ATPases/metabolism*
  • Zebrafish/metabolism*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed
32328632 Full text @ J. Cell Biol.
Abstract
Epithelial cell physiology critically depends on the asymmetric distribution of channels and transporters. However, the mechanisms targeting membrane proteins to the apical surface are still poorly understood. Here, we performed a visual forward genetic screen in the zebrafish intestine and identified mutants with defective apical targeting of membrane proteins. One of these mutants, affecting the vacuolar H+-ATPase gene atp6ap1b, revealed specific requirements for luminal acidification in apical, but not basolateral, membrane protein sorting and transport. Using a low temperature block assay combined with genetic and pharmacologic perturbation of luminal pH, we monitored transport of newly synthesized membrane proteins from the TGN to apical membrane in live zebrafish. We show that vacuolar H+-ATPase activity regulates sorting of O-glycosylated proteins at the TGN, as well as Rab8-dependent post-Golgi trafficking of different classes of apical membrane proteins. Thus, luminal acidification plays distinct and specific roles in apical membrane biogenesis.
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