N-terminal PDZ domain is required for NHERF dimerization

NHERF, a 55 kDa PDZ-containing protein, binds receptors and ion transporter s to mediate signal transduction at the plasma membrane. Recombinant NHERF demonstrated an apparent size of 150 kDa on gel filtration, which could be reduced to approximately 55 kDa by protein denaturing agents, consistent wi th the formation of NHERF dimers, Biosensor studies established the time- a nd concentration-dependent dimerization of NHERF. Overlays of recombinant N HERF fragments suggested that NHERF dimerization was principally mediated b y the N-terminal PDZ-I domain. In PS120 cells, reversible protein phosphory lation modulated NHERF dimerization and suggested a role for NHERF dimers i n hormonal signaling. (C) 2001 Federation of European Biochemical Societies . Published by Elsevier Science B.V. All rights reserved.