The human genome encodes at least three non-allellic G proteins with αi-type subunits

Wadi N. Suki, Joel Abramowitz, Rafael Mattera, Juan Codina, Lutz Birnbaumer

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


The amino acid sequence and composition of α-subunits of signal transducing G proteins of the same kind appear to vary by no more than 2% from species to species. Here we isolated a human liver cDNA using an oligonucleotide complementary to the sequences encoding the pertussis toxin (PTX) ADP-ribosylation site of the α-subunit of the rat brain G protein called Gi. Its open reading frame characterizes it as an αi-type cDNA-as opposed to αo-type-but predicts an amino acid composition that differs by 7% and 14%, respectively, from two other human αi-type molecules. Together with human brain αi (type-1) and human monocyte αi (type-2), the new human liver αi cDNA (type-3) forms part of a family of αi molecules. Type-3 αi cDNA hybridizes to a ∼ 3.6 kilobase long mRNA and type-2 αi cDNA hybridizes to an mRNA species of ∼ 2.7 kilobases. This indicates that the human genome has at least three non-allellic genes encoding non-αo-type PTX substrates and provides structural evidence for the hypothesis that distinct effector systems are regulated by similar but nevertheless distinct PTX substrates.

Original languageEnglish (US)
Pages (from-to)187-192
Number of pages6
JournalFEBS Letters
Issue number1
StatePublished - Aug 10 1987


  • Adenylyl cyclase
  • G protein
  • K channel
  • Pertussis toxin
  • Phospholipase A
  • Phospholipase C

ASJC Scopus subject areas

  • Molecular Biology
  • Biophysics
  • Biochemistry


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