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 (By similarity). Required for normal chemotaxis in response to cAMP and for aggregation during scorocarp development. G proteins are composed of 3 units, alpha, beta and gamma. Interacts with gpgA, and this requires phlp1. Membrane-associated protein is concentrated at the anterior of polarized cells. Expressed throughout development. Expression rises within 6 hours after the initiation of development and gradually decreases following the mound stage. Expressed in vegetative cells. Belongs to the WD repeat G protein beta family.