Amphioxus expresses both vertebrate-type and invertebrate-type dopamine D(1) receptors.
The cephalochordate amphioxus (Branchiostoma floridae) has recently been placed as the most basal of all the chordates, which makes it an ideal organism for studying the molecular basis of the evolutionary transition from invertebrates to vertebrates. The biogenic amine, dopamine regulates many aspects of motor control in both vertebrates and invertebrates, and in both cases, its receptors can be divided into two main groups (D1 and D2) based on sequence similarity, ligand affinity and effector coupling. A bioinformatic study shows that amphioxus has at least three dopamine D1-like receptor sequences. We have recently characterized one of these receptors, AmphiD1/β, which was found to have high levels of sequence similarity to both vertebrate D1 receptors and to β-adrenergic receptors, but functionally appeared to be a vertebrate-type dopamine D(1) receptor. Here, we report on the cloning of two further dopamine D(1) receptors (AmphiAmR1 and AmphiAmR2) from adult amphioxus cDNA libraries and their pharmacological characterisation subsequent to their expression in cell lines. AmphiAmR1 shows closer structural similarities to vertebrate D(1)-like receptors but shows some pharmacological similarities to invertebrate "DOP1" dopamine D(1)-like receptors. In contrast, AmphiAmR2 shows closer structural and pharmacological similarities to invertebrate "INDR"-like dopamine D(1)-like receptors.
The Inositide Laboratory, The Babraham Institute, The Babraham Research Campus, Cambridge CB22 3AT, UK.
Chloe
C
Burman
Peter D
PD
Evans
D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D002816:Chordata, Nonvertebrate / Q000235:genetics / Q000378:metabolism*; D019976:Cloning, Organism; D000242:Cyclic AMP / Q000378:metabolism; D004298:Dopamine / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D010802:Phylogeny; D011943:Receptors, Adrenergic, beta / Q000235:genetics / Q000378:metabolism; D017447:Receptors, Dopamine D1 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D011943:Receptors, Adrenergic, beta; D017447:Receptors, Dopamine D1; D000242:Cyclic AMP; D048049:Extracellular Signal-Regulated MAP Kinases; D004298:Dopamine