Skip to main content
. 2018 Apr 23;115(19):5022–5027. doi: 10.1073/pnas.1722498115

Fig. 4.

Fig. 4.

Reduction of group III mGluRs efficacy by ELFN1 is not a consequence of altered desensitization. (A) Schematic representation of transcellular GPCR signaling assay involving coculture of control cells or ELFN1-expressing cells with mGluR6-expressing cells coexpressing BRET-based Nluc-EPAC-VV cAMP biosensor. (B) Change in BRET ratio measurements over time of cells pretreated with buffer or 300 µM l-glutamic acid for 5 min and then stimulated with 1 µM forskolin, with increased cAMP equating to decreased BRET ratio. mGluR activation was quantified as a decrease in forskolin response. (C) Quantification of mGluR6 activation following coculture with control or ELFN1-expressing cells. (D) Change in BRET ratio readings following adaptation of assay to accommodate longitudinal prestimulations with 300 µM l-glutamic acid. The solid control line corresponds to no prestimulation/baseline in the presence of control cells, followed by 5, 30, or 60 min of l-glutamic acid prestimulation, with 5 min providing the maximum (Max) response. (E) Change in BRET ratio under the same parameters in parallel in the presence of ELFN1-expressing cells. (F) Quantification of mGluR6 activation normalizing for Max response (5 min).