Fig. 1

POPDC proteins pull down and co-immunoprecipitate XIRP1 and pull down annexin A5 from human myotube extract and pull-down XIRP1 from rat heart extract. Vertical black lines separate parts of blots that were originally non-adjacent or with different exposure times, as described. In all cases, the molecular weight markers in lane 1 were detected by colourimetric imaging and the antibody blots by chemiluminescence. a Glutathione beads were loaded with recombinant preparations of POPDC1, POPDC2 or not loaded (control for non-specific binding) and incubated with human myotube extracts. “Input” shows human myotube extracts diluted to 20%. Upper part of blot (A) (above 72 kDa) developed with mAb against XIRP1 (sc-166,658) shows XIRP1 in the input and pulled down by POPDC1 and POPDC2, but not in the control. The “Input” lane had a shorter exposure time than the others and the “Control” lane was originally non-adjacent. The Lower part of blot (A) (72 kDa and below) was from a separate but identical gel to the upper blot and was developed with mAb against GST tag (17A10) as a loading control. The “Control” lane was originally non-adjacent to the others. The predicted molecular weights of the Popdc1 and Popdc2 fusion proteins are 58 and 57 kDa respectively, which are indicated approximately with a single arrow. b Pan mouse IgG Dynabeads were loaded with monoclonal antibody against POPDC1 (1C12) or not loaded (control) and incubated with human myotube extracts. The blot was developed with XIRP1 mAb and shows XIRP1 in the input and immunoprecipitated by the POPDC1 mAb but not by unloaded control beads. * = mouse Ig H and L chains. Predicted molecular weights of human XIRP1, isoforms 1,2 and 3 are 199, 122 and 56 kDa respectively. Arrows indicate bands corresponding to XIRP1 isoforms 1 and 3. The “POPDC1 1C12” lane had a longer exposure compared to the other lanes and the “molecular weight markers” were not originally in lane 1. c Glutathione beads loaded with recombinant POPDC1 or beads alone (control) were incubated with human myotube extract. The blot was developed with pAb against annexin A5. The arrow indicates a band corresponding to annexin A5 monomer (36 kDa) in the input and POPDC1 pull-down, but absent from the non-specific binding control. The “Control” lane was originally non-adjacent to the others. d Glutathione beads loaded with recombinant POPDC1 or beads alone (control) were incubated with rat heart ventricle extract. The blot was developed with mAb against XIRP1. Arrows indicate bands corresponding to XIRP1 in the input and POPDC1 pull-down, but absent from the non-specific binding control. The original colourimetric and chemiluminescence images are shown in Additional File 2