PMCA1 binding to NHERF-2 in HT-29 cells is mediated by the C-terminal
PDZ motif. A, GST pull-downs using pan-PMCA antibody showing that
PMCA interacted with NHERF-2 but not NHERF-1 in HT-29 cells, and the
interaction was mediated by the second PDZ module (PDZ2) of NHERF-2.
B, co-immunoprecipitations investigating the interaction between
NHERF1/2 and PMCA. Lane a, HT-29 cell lysate control; lanes
b and c, immunoprecipitation with anti-NHERF-1 antibody;
lanes d and e, immunoprecipitation with anti-NHERF-2
antibody. B, panel i, blot probed with pan-PMCA antibody.
B, panel ii, blot probed with anti-PMCA4 antibody. NHERF-2
interacted with PMCA, and this interaction occurred in the presence and
absence of ACh. C, Western blot showing HEK293 cells transfected with
GFP-tagged PMCA1b C terminus ± PDZ binding motif expressed proteins of
the predicted size (∼50 kDa). D, pull-downs using GFP constructs
of the C terminus of PMCA1b ± PDZ binding motif together with
GST-NHERF-2. The interaction with NHERF-2 was abolished when the C-terminal
ETSL motif was deleted (GFP-PMCA1b-DPDZ). Western blots are representative of
at least three individual experiments.