We have investigated whether the 14-3-3 protein binding affects the structure of RGS3 using the time-resolved tryptophan fluorescence spectroscopy and X-ray protein crystallography. Our results revealed that the 14-3-3 protein binding induces structural changes in both the N-terminal part and the C-terminal RGS domain of phosphorylated RGS3 molecule.
The data obtained from the resolution of the crystal structure of the RGS domain suggest that the 14-3-3 protein-induced conformational change affects the region within the G(alpha)-interacting portion of the RGS domain. This can explain the inhibitory effect of the 14-3-3 protein on GAP activity of RGS3.