Crystallographic characterization of the radixin FERM domain bound to the C-terminal region of the human Na+/H+-exchanger regulatory factor (NHERF).

Radixin is a member of the ERM proteins, which cross-link plasma membranes and actin filaments. The N-terminal FERM domains of ERM proteins interact with Na(+)/H(+)-exchanger regulatory factors (NHERFs), which are PDZ-containing adaptor proteins, to modulate the ion-channel activity. Here, crystals of complexes between the radixin FERM domain and the C-terminal regions of NHERF and NHERF2 have been obtained. The crystals of the FERM-NHERF complex were found to belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 69.38 (2), b = 146.27 (4), c = 177.76 (7) A. The crystal contains four complexes in the asymmetric unit. An intensity data set was collected to a resolution of 2.50 A.