Dataset for: Characterization of a Novel Signal Transducer Element Intrinsic to Class IIIa/b Adenylate Cyclases and Guanylate Cyclases
2017-05-12T08:45:42Z (GMT) by
Adenylate cyclases (ACs) are signalling proteins that produce the second messenger cAMP. Class III ACs comprises four groups (class IIIa-d); of these, class IIIa and IIIb ACs have been identified in bacteria and eukaryotes. Many class IIIa ACs are anchored to membranes via hexahelical domains. In eukaryotic ACs, membrane anchors are well conserved, suggesting that this region possesses important functional characteristics that are as yet unknown. To address this question, we replaced the hexahelical membrane anchor of the mycobacterial AC Rv1625c by the hexahelical quorum-sensing receptor from Legionella, LqsS. Using this chimera, we identified a novel 19-amino-acid cyclase-transducer element located N-terminally to the catalytic domain that links receptor stimulation to effector activation. Coupling of the receptor to the AC was possible at several positions distal to the membrane exit resulting in stimulatory or inhibitory responses to the ligand Legionella AutoInducer-1 (LAI-1). In contrast, on the AC effector side functional coupling was only successful when starting with the cyclase-transducer element. Bioinformatics approaches established that distinct cyclase-transducer elements are universally present in class IIIa and IIIb ACs and in vertebrate guanylate cyclases. The data suggest that membrane-delimited receiver domains transduce regulatory signals to the downstream catalytic domains in an engineered AC model system. This may forecast a previously unknown mechanism for cellular cAMP regulation.