Figure 3. Mapping of interaction between hFMRP and hCaprin1 in pulldown assays. A.

) Pulldown assay using 1 µg of the fusion protein GST-Caprin1 immobilized on beads and in vivo translated ³⁵S-labelled full length FMRP (FL) and its truncated and deleted versions. B) Reverse pulldown assay using immobilized GST-FMRP incubated with ³⁵S-labeled full length Caprin1 (FL) and its truncated and deleted versions. In both cases, ³⁵S-labeled Luciferase (Luc) was used as a negative control. C) Schematic diagram summarizing the data presented in A and B. D) Refine region in FMRP NES (amino acids residues 424–440) required for binding to Caprin1. E) The interaction of FMRP with Caprin1 is stable in the presence of 400 mM NaCl. F) The interaction of Caprin1 and FMRP is direct in a pulldown assay using recombinant proteins.