Yeast Aquaglyceroporins Use the Transmembrane Core to Restrict Glycerol Transport
Artikel i vetenskaplig tidskrift, 2012

Aquaglyceroporins are transmembrane proteins belonging to the family of aquaporins, which facilitate the passage of specific uncharged solutes across membranes of cells. The yeast aquaglyceroporin Fps1 is important for osmoadaptation by regulating intracellular glycerol levels during changes in external osmolarity. Upon high osmolarity conditions, yeast accumulates glycerol by increased production of the osmolyte and by restricting glycerol efflux through Fps1. The extended cytosolic termini of Fps1 contain short domains that are important for regulating glycerol flux through the channel. Here we show that the transmembrane core of the protein plays an equally important role. The evidence is based on results from an intragenic suppressor mutation screen and domain swapping between the regulated variant of Fps1 from Saccharomyces cerevisiae and the hyperactive Fps1 ortholog from Ashbya gossypii. This suggests a novel mechanism for regulation of glycerol flux in yeast, where the termini alone are not sufficient to restrict Fps1 transport. We propose that glycerol flux through the channel is regulated by interplay between the transmembrane helices and the termini. This mechanism enables yeast cells to fine-tune intracellular glycerol levels at a wide range of extracellular osmolarities.

eston gm

regulatory domain

proceedings of the national academy of sciences of the united states

1991

channel

facilitator

aquaporin

fungus ashbya-gossypii

membrane

osmotic-stress

selectivity

fps1p

mechanism

protein

Författare

Cecilia Geijer

Göteborgs universitet

Doryaneh Ahmadpour

Göteborgs universitet

Madelene Palmgren

Göteborgs universitet

Caroline Filipsson

Göteborgs universitet

Dagmara Medrala Klein

Göteborgs universitet

Markus J. Tamás

Göteborgs universitet

Stefan Hohmann

Göteborgs universitet

Karin Lindkvist-Petersson

Göteborgs universitet

Journal of Biological Chemistry

0021-9258 (ISSN) 1083-351X (eISSN)

Vol. 287 23562-23570

Ämneskategorier

Biokemi och molekylärbiologi

DOI

10.1074/jbc.M112.353482