G Protein binding sites on Calnuc (nucleobindin 1) and NUCB2 (nucleobindin 2) define a new class of G(alpha)i-regulatory motifs.

ABSTRACT: Heterotrimeric G proteins are molecular switches modulated by families of structurally and functionally related regulators. GIV (Gα-interacting vesicle-associated protein) is the first non-receptor guanine nucleotide exchange factor (GEF) that activates Gα(i) subunits via a defined, evolutionarily conserved motif. Here we found that Calnuc and NUCB2, two highly homologous calcium-binding proteins, share a common motif with GIV for Gα(i) binding and activation. Bioinformatics searches and structural analysis revealed that Calnuc and NUCB2 possess an evolutionarily conserved motif with sequence and structural similarity to the GEF sequence of GIV. Using in vitro pulldown and competition assays, we demonstrate that this motif binds preferentially to the inactive conformation of Gα(i1) and Gα(

SUBMITTER: Garcia-Marcos M 

PROVIDER: S-EPMC3151059 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature