Characterization of structural determinants of type 1 corticotropin releasing hormone (CRH) receptor signalling properties.
Mammalian adaptation to stressful stimuli requires activation of the type 1 corticotropin releasing hormone (CRH) receptor (CRH-R1), a 415 amino acid protein that belongs to the large superfamily of 7 transmembrane domain receptors that relay signals across cells through activation of G-proteins. CRH-R1 expression and activity is regulated at the gene level by mRNA alternative splicing that results in a number of CRH-R1 variants. This process can generate putative CRH-R1 receptor variants with distinct structural and signaling properties; their study can provide important insights about the structural determinants of CRH-R1 functional characteristics. Using site-directed mutagenesis by overlap extension polymerase chain reaction (OE-PCR), we investigated the structure-function relationships of a CRH-R1 variant with an extended 1st intracellular loop (IC1) (CRH-R1beta), a sequence modification that impairs signaling activity (such as cAMP production and MAPK activation). We identified a penta-amino acid cassette within the 29-amino acid insert of CRH-R1beta rich in positive charged amino acids (F(170)-R(174)), as an important structural determinant for the impaired cAMP response.
Markovic
Danijela
D
Department of Cell Physiology and Pharmacology, University of Leicester, Leicester, UK. mdanijela73@googlemail.com
Grammatopoulos
Dimitris K
DK
D017398:Alternative Splicing; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D018019:Receptors, Corticotropin-Releasing Hormone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D000099052:CRF Receptor, Type 1
D018019:Receptors, Corticotropin-Releasing Hormone; D000099052:CRF Receptor, Type 1