Heterotrimeric G proteins (Gαβγ) play an essential role in coupling membrane receptors to effector proteins such as ion channels and enzymes. Among the five mammalian Gβ-subunits cloned, the human G protein β4 has not been described. The purpose of the present study was to functionally characterize the newly identified human Gβ4 subunit. The Gβ4 open reading frame (ORF) was amplified utilizing PCR from brain cDNA. Amplification primers were generated following 5′ rapid amplification of cDNA ends (5′-RACE) from an expressed sequence tag (EST) containing the predicted 3′ end of the protein. Multiple tissue cDNA panel analysis showed that Gβ4 mRNA was strongly expressed in lung and placenta, whereas it is weakly expressed in brain and heart. Heterologous overexpression of Gβ4γ2 or Gβ4γ4 in rat sympathetic neurons resulted in tonic modulation of N-type voltage-gated Ca2+ and G protein-gated inwardly rectifying K+ currents. Furthermore, coexpression of Gβ4γ2 and GαoA resulted in heterotrimer formation. These results show that the newly cloned Gβ4 subunit hares several properties with other human Gβ family members.
|Original language||English (US)|
|Number of pages||10|
|State||Published - Apr 2002|
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