5-HT7 Receptor - Variants

Variants

Three splice variants have been identified in humans (designated h5-HT_7(a), h5-HT_7(b), and h5-HT_7(d)), which encode receptors that differ in their carboxy terminals. The h5-HT_7(a) is the full length receptor (445 amino acids), while the h5-HT_7(b) is truncated at amino acid 432 due to alternative splice donor site. The h5-HT_7(d) is a distinct isoform of the receptor: the retention of an exon cassette in the region encoding the carboxyl terminal results a 479-amino acid receptor with a c-terminus markedly different from the h5-HT_7(a). A 5-HT_7(c) splice variant is detectable in rat tissue but is not expressed in humans. Conversely, rats do not express a splice variant homologous to the h5-HT_7(d), as the rat 5-HT₇ gene lacks the exon necessary to encode this isoform. Drug binding affinities are similar across the three human splice variants; however, inverse agonist efficacies appear to differ between the splice variants.