A critical challenge of structural genomics is to extract functional inform
ation from protein structures. We present an example of how this may be acc
omplished using the Evolutionary Trace (ET) method in the context of the re
gulators of G protein signaling (RGS) family. We have previously applied ET
to the RGS family and identified a novel, evolutionarily privileged site o
n the RGS domain as important for regulating RGS activity. Here we confirm
through targeted mutagenesis of RGS7 that these ET-identified residues are
critical for RGS domain regulation and are likely to function as global det
erminants of RGS function. We also discuss how the recent structure of the
complex of RGS9, G(t/11 alpha)-GDP-AlF4- and the effector subunit PDE gamma
confirms their contact with the effector-G protein interface, forming a st
ructural pathway that communicates from the effector-contacting surface of
the G protein and RGS catalytic core domain to the catalytic interface betw
een G(alpha) and RGS. These results demonstrate the effectiveness of ET for
identifying binding sites and efficiently focusing mutational studies on t
heir key residues, thereby linking raw sequence and structure data to funct
ional information.