Cloned human receptors receptor phosphorylation

CRF, receptors (formerly called CRF-RA or PC-CRF) have been cloned from several species. The species homologues are 98% identical over their 415 amino acid sequences. There are a number of potential phosphorylation and glycosylation sites within the sequences that would allow regulation. An alternative transcript form of this receptor has been identified in human pituitary, which contains an additional 29 amino acids in the first intracellular loop the significance of this form is not known. 

The human and rat 5-HT4 receptor was recently cloned and expressed [60,61]. Two splice variants of the 5-HT4 receptor of the rat have been isolated 5-HT4S encoding 387 amino acids and 5-HT4L encoding 406 amino acids. The long isoform contains a protein kinase C phosphorylation site in the C-terminal which is not present in the short isoform [61]. The 5-HT4 receptors are positively coupled to adenylylcyclase. Functionally the 5-HT4 receptors are similar to the 5-HT6 and 5-HT7 receptors. 

---