title: Functional analysis of the distal region of the third intracellular loop of PROKR2.
abstract: Mutations in the G-protein-coupled receptor PROKR2 have been identified in patients with idiopathic hypogonadotropic hypogonadism (IHH) and Kallmann syndrome (KS) manifesting with delayed puberty and infertility. Recently, the homozygous mutation V274D was identified in a man displaying KS with an apparent reversal of hypogonadism. The affected amino acid, valine 274, is located at the junction region of the third intracellular loop (IL3) and the sixth transmembrane domain (TM6). In this study, we first studied the effect of V274D and related mutations (V274A, V274T, and V274R) on the signaling activity and cell surface expression of PROKR2. Our data indicate that a charged amino acid substitution at residue 274 of PROKR2 results in low cell surface expression and loss-of-function. Furthermore, we studied the effects of two clusters of basic amino acids located at the proximal region of Val274 on the cell surface expression and function of PROKR2. The deletion of RRK (270-272) resulted in undetectable cell surface expression, whereas RKR (264-266)-deleted PROKR2 was expressed normally on the cell surface but showed loss-of-function due to a deficiency in G-protein coupling. Our data indicate that the distal region of the IL3 of PROKR2 may differentially influence receptor trafficking and G-protein coupling.
authors: Xiangya Hospital, State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan Province 410078, PR China; Department of Immunology, Xinjiang Medical University, Urumqi, Xinjiang Uygur Autonomous Region 830054, PR China.
authors: Xiao-Tao
authors: XT
authors: Zhou
authors: Dan-Na
authors: DN
authors: Chen
authors: Zhi-Qun
authors: ZQ
authors: Xie
authors: Zhen
authors: Z
authors: Peng
authors: Kai-De
authors: KD
authors: Xia
authors: Hua-Die
authors: HD
authors: Liu
authors: Wei
authors: W
authors: Liu
authors: Bing
authors: B
authors: Su
authors: Jia-Da
authors: JD
authors: Li
mesh_terms: D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D002462:Cell Membrane / Q000378:metabolism; D017353:Gene Deletion; D057809:HEK293 Cells; D006801:Humans; D007006:Hypogonadism / Q000235:genetics; D017436:Kallmann Syndrome / Q000235:genetics; D008958:Models, Molecular; D009154:Mutation; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry* / Q000502:physiology; D018000:Receptors, Peptide / Q000737:chemistry* / Q000502:physiology; D015398:Signal Transduction; D014633:Valine / Q000737:chemistry
chemical_list: C470838:PROKR2 protein, human; D021382:Protein Sorting Signals; D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; D014633:Valine
keywords: ER; G-protein-coupled receptor; GPCR; HEK; IHH; IL; Intracellular loop; KS; Kallmann syndrome; MAPK; PK2; PROKR2; Prokineticin 2; Prokineticin receptor 2; TM; WT; endoplasmic reticulum; human embryonic kidney; idiopathic hypogonadotropic hypogonadism; intracellular loop; mitogen-activated protein kinase; transmembrane domain; wild-type