E and M circadian pacemaker neurons use different PDF receptor signalosome components in drosophila.
We used real-time imaging to detect cAMP levels in neurons of intact fly brains to study the mechanisms of circadian pacemaker synchronization by the neuropeptide pigment dispersing factor (PDF) in Drosophila. PDF receptor (PDF-R) is expressed by both M (sLNv) and E (LNd) pacemaker subclasses and is coupled to G(sα) in both cases. We previously reported that PDF-R in M pacemakers elevates cAMP levels by activating the ortholog of mammalian adenylate cyclase 3 (AC3) but that AC3 disruptions had no effect on E pacemaker sensitivity to PDF. Here, we show that PDF-R in E pacemakers activates a different AC isoform, AC78C, an ortholog of mammalian AC8. Knockdown of AC78C by transgenic RNAi substantially reduces, but does not completely abrogate, PDF responses in these E pacemakers. The knockdown effect is intact when restricted to mature stages, suggesting a physiological and not a development role for AC78C in E pacemakers. The AC78C phenotype is rescued by the overexpression of AC78C but not by overexpression of the rutabaga AC. AC78C overexpression does not disrupt PDF responses in these E pacemakers, and neither AC78C knockdown nor its overexpression disrupted locomotor rhythms. Finally, knockdown of 2 AKAPs, nervy and AKAP200, partially reduces LNd PDF responses. These findings begin to identify the components of E pacemaker PDF-R signalosomes and indicate that they are distinct from PDF-R signalosomes in M pacemakers: we propose they contain AC78C and at least 1 other AC.
['Duvall|Laura B|LB|', 'Taghert|Paul H|PH|']
D054758:A Kinase Anchor Proteins D048868:Adaptor Proteins, Signal Transducing D000262:Adenylyl Cyclases D000818:Animals D001921:Brain D002940:Circadian Rhythm D003627:Data Interpretation, Statistical D004330:Drosophila D029721:Drosophila Proteins D031541:Fluorescence Resonance Energy Transfer D015870:Gene Expression D007091:Image Processing, Computer-Assisted D008297:Male D008565:Membrane Proteins D009043:Motor Activity D059906:Neuroimaging D009474:Neurons D034622:RNA Interference D043562:Receptors, G-Protein-Coupled
signalosomes pacemaker synchronization neuropeptide pigment dispersing factor Drosophila melanogaster circadian circuit