Figure 5
From: Genetic basis of functional variability in adhesion G protein-coupled receptors
Functional impact of N- and C terminus length variations in mouse ADGRF5/GPR116. Splice variant analysis of Adgrf5/Gpr116 revealed several variations of the N- and C terminus lengths. Selected variants were tested in respect to their cell surface expression and signal transduction properties. The common N-terminal variants ADGRF5-1-3, a rare variant that lacks the third Ig domain (ADGRF5-20, suppl. Table S3 Adgrf5/Gpr116 variant fat 2_6) and the empty vector (pcDps) were tested in (A) cell surface expression ELISA and (B) inositol phosphate (IP1) assays. In IP1 assays the variants were analyzed without (w/o) and with the Stachel peptide of GPR116 (1 mM) or a scrambled peptide as control (1 mM). Similarly, four selected mouse GPR116 variants differing in their C-terminus lengths were tested. C-Term-1 and C-Term-2 correspond to ADGRF5-1-9, -15, -18, -19 and ADGRF5-10, -13, -14, -16, -17 of Fig. 2, respectively. C-Term-3 and C-Term-4 were rare splice variants (<1% of all GPR116 transcripts) in the data sets we analyzed. (C) Cell surface expression (ELISA) and (D) agonist-induced inositol phosphate (IP1) accumulation assays were performed. Data are given as means ± S.E.M. ELISA OD pcDps: 0.006 ± 0.003 (N-Term) and 0.008 ± 0.004 (C-Term), AGDRF5-2: 0.120 ± 0.021, C-Term-1: 0.105 ± 0.023; as positive control (not shown) the HA-tagged ADP receptor P2RY12 showed an OD value of 0.322 ± 0.041. IP1: pcDps w/o: 215 ± 37 nM, n ≥ 4 (C-Term) and n ≥ 5 (N-Term).
