Alternative Splicing Produces Transcripts Encoding Two Forms of the α Subunit of GTP-Binding Protein Go

The α subunit of the guanine nucleotide-binding protein Go("o" for other) is believed to mediate signal transduction between a variety of receptors and effectors. cDNA clones encoding two forms of Goα subunit were isolated from a mouse brain library. These two forms, which we call GoAα and GoBα, appear to be the products of alternative splicing. GoAα differs from GoBα over the C-terminal third of the deduced protein sequence. Both forms are predicted to be substrates for ADP-ribosylation by pertussis toxin. GoAα transcripts are present in a variety of tissues but are most abundant in brain. The GoBα transcript is expressed at highest levels in brain and testis. It is possible that GoAα and GoBα have different functions.