Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction. G proteins are composed of 3 units, alpha, beta and gamma (By similarity). The heterodimer formed by GNB1 and GNG2 interacts with ARHGEF5 (By similarity). The heterodimer formed by GNB1 and GNG2 interacts with GRK2 (By similarity). Interacts with ARHGEF18 and RASD2 (By similarity). Phosphorylation at His-266 by NDKB contributes to G protein activation by increasing the high energetic phosphate transfer onto GDP. Belongs to the WD repeat G protein beta family.