Human G protein gamma(11) and gamma(14) subtypes define a new functional subclass

The mammalian gamma subunit family consists of a minimum of 12 members. Ana lysis of the amino acid sequence conservation suggests that the gamma subun it family can be divided into three distinct subclasses. The division of th e gamma subunit family into these classes is based not only on amino acid h omology, but also to some extent on functional similarities. In the present study, two new members of the gamma subunit family, the gamma(11) and gamm a(14) subunits, are identified and characterized in terms of their expressi on and function. The gamma(11) and gamma(14) subunits are most closely rela ted to the gamma(1) subunit and share similar biochemical properties, sugge sting their inclusion in class I. However, despite their close phylogenetic relationship and similar biochemical properties, the gamma(1), gamma(11), and gamma(14) subunits exhibit very distinct expression patterns, suggestin g that class I should be further subdivided and that the signaling function s of each subgroup are distinct. In this regard, the gamma(11) and gamma(14 ) subunits represent a new subgroup of farnesylated gamma subunits that are expressed outside the retina and have functions other than phototransducti on. (C) 2000 Academic Press.