Identification of residues controlling transport through the yeast aquaglyceroporin Fps1 using a genetic screen
Artikel i vetenskaplig tidskrift, 2004

Aquaporins and aquaglyceroporins mediate the transport of water and solutes across biological membranes. Saccharomyces cerevisiae Fps1 is an aquaglyceroporin that mediates controlled glycerol export during osmoregulation. The transport function of Fps1 is rapidly regulated by osmotic changes in an apparently unique way and distinct regions within the long N- and C-terminal extensions are needed for this regulation. In order to learn more about the mechanisms that control Fps1 we have set up a genetic screen for hyperactive Fps1 and isolated mutations in 14 distinct residues, all facing the inside of the cell. Five of the residues lie within the previously characterized N-terminal regulatory domain and two mutations are located within the approach to the first transmembrane domain. Three mutations cause truncation of the C-terminus, confirming previous studies on the importance of this region for channel control. Furthermore, the novel mutations identify two conserved residues in the channel-forming B-loop as critical for channel control. Structural modelling-based rationalization of the observed mutations supports the notion that the N-terminal regulatory domain and the B-loop could interact in channel control. Our findings provide a framework for further genetic and structural analysis to better understand the mechanism that controls Fps1 function by osmotic changes

aquaglyceroporin

channel

osmoregulation

glycerol

genetic screen

Författare

Sara Karlgren

Göteborgs universitet

Caroline Filipsson

Göteborgs universitet

Jonathan G.L. Mullins

R Bill

Markus J. Tamás

Göteborgs universitet

Stefan Hohmann

Göteborgs universitet

European journal of biochemistry

Vol. 271 4 771-779

Ämneskategorier

Biologiska vetenskaper

DOI

10.1111/j.1432-1033.2004.03980.x