Poster: Membrane Transport

Abs # 1240: Plant aquaporins - Structure and post-translational regulation of a plasma membrane water channel

Presenter:	Kjellbom, Per , per.kjellbom@plantbio.lu.se
Authors	Kjellbom, Per  (A)   Karlsson, Maria  (A)   Fotiadis, Dimitrios  (B)   Engel, Andreas  (B)   Johansson, Ingela  (A)   Alexandersson, Erik  (A)   Sjovall, Sara  (A)   Gustavsson, Sofia  (A)   Fraysse, Laure  (A)   Johanson, Urban  (A)
Affiliations:	(A): Department of Plant Biochemistry, Lund University (B): M E Muller-Institute for Microscopy, Biozentrum. University of Basel, Switzerland

In Arabidopsis thaliana 35 genes have been found that code for aquaporin homologues. Some of these genes code for highly abundant constitutively expressed proteins and some genes are known to be temporally and spatially regulated during development and in response to stress. At a given time, cells express several different aquaporins and it is likely that vacuolar and plasma membrane aquaporins acting in concert are responsible for cytosolic osmoregulation necessary for maintaining normal metabolic processes. Inhibition studies of aquaporins in vivo and antisense mutant studies suggest that, in addition to cytosolic osmoregulation, aquaporins are important for the bulk flow of water in plants and for water homeostasis. The water transport activity of one plasma membrane aquaporin is regulated at the protein level by phosphorylation and dephosphorylation. Structure data from 2D crystals using atomic force microscopy and results concerning post-translational regulation of this plasma membrane aquaporin will be discussed in detail.