26.9 Monday, Jan. 5 EVOLUTION OF GLYCOPROTEIN HORMONE/GLYCOPROTEIN HORMONE RECEPTOR SYSTEMS IN VERTEBRATES FROM A SEA LAMPREY PERSPECTIVE FREAMAT, Mihael*; SOWER, Stacia A.; University of New Hampshire, Durham; University of New Hampshire Durham email@example.com
The endocrine control of the gonadal and thyroid physiology in vertebrates depends ultimately on the interaction between the pituitary glycoprotein hormones (GpH) and their cognate receptors (GpH-R). Both ligands and receptors are closely related proteins, with similar overall structural organization. Subtle differences between their structures result in a high degree of selectivity in the activating interactions hormone/receptor which ensures a minimal cross interaction between these pathways in later evolved vertebrates. This selectivity however was found to be less stringent in earlier evolved vertebrates. Investigation of the GpH/GpH-R system in the sea lamprey resulted in identification of one GpH and of two GpH-R homologs. We present the structural and functional properties of these molecules and their implications for understanding of the origins of pituitary-gonadal/thyroid axes, of the mechanisms of functional divergence of related receptors and evolution of complex chemical signaling networks. Supported by NSF IBN-0421923 and NH AES Hatch #332.