Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. In the 1-cell embryo, probably together with goa-1, controls nuclear rotation and spindle elongation during mitosis. During the first embryonic cell divisons, plays a role in gpr-1/2 cortical localization and in the proper orientation of EMS blastomere mitotic spindle. G proteins are composed of 3 units; alpha, beta and gamma. The alpha chain contains the guanine nucleotide binding site. Belongs to the G-alpha family.