Skip to main content
. 2019 Jul 9;17(7):e3000332. doi: 10.1371/journal.pbio.3000332

Fig 4. Cyclen antagonized spermine-induced cAMP responses to receptor TAAR348.

Fig 4

(A) Cyclen treatment inhibited cAMP production induced by 0.1 mM spermine in TAAR348-expressing HEK293T cells as measured with a TR-FRET assay and normalized to the cAMP level in buffer-treated cells (mean ± SEM, n = 5). The filled triangle represents cAMP production induced by 0.1 mM spermine in the cells without exposure to cyclen. Fold increase over basal was calculated as [(measured cAMP − basal cAMP) ÷ basal cAMP] − 1. (B) Cyclen did not induce cAMP production in HEK293T with TAAR348 (mean ± SEM; reads from triplicate wells). (Inset) Structure of cyclen (1,4,7,10-tetraazacyclododecane). (C) Cadaverine induced cAMP production in a concentration-dependent manner in HEK293T cells expressing another sea lamprey TAAR-like gene—TAAR346a (mean ± SEM, n = 5). (D) Cyclen treatment did not inhibit cAMP production induced by 1 mM of cadaverine in HEK293T cells expressing TAAR346a. The filled triangle represents the cAMP production induced by 1 mM of cadaverine in the cells without exposure to cyclen (mean ± SEM, n = 5). Underlying data are available in S1 Data. cAMP, cyclic-adenosine monophosphate; HEK293T, human embryonic kidney 293T; TAAR, trace amine-associated receptor; TR-FRET, time-resolved fluorescence energy transfer.