QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online November 30, 2007
Journal of Experimental Biology 210, 4465-4470 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.012088

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Isaac, R. E. Articles by Shirras, A. D. Search for Related Content PubMed PubMed Citation Articles by Isaac, R. E. Articles by Shirras, A. D. Social Bookmarking                         What's this?

Metabolic inactivation of the circadian transmitter, pigment dispersing factor (PDF), by neprilysin-like peptidases in Drosophila

R. Elwyn Isaac^1,*, Erik C. Johnson², Neil Audsley³ and Alan D. Shirras⁴

¹ Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
² Department of Biology, Wake Forest University, NC, USA
³ Central Science Laboratory, Sand Hutton, York, YO41 1LZ, UK
⁴ Department of Biological Sciences, University of Lancaster, LA1 4YQ, UK

^* Author for correspondence (e-mail: r.e.isaac{at}leeds.ac.uk)

Accepted 4 October 2007

Recent studies have firmly established pigment dispersing factor (PDF), a C-terminally amidated octodecapeptide, as a key neurotransmitter regulating rhythmic circadian locomotory behaviours in adult Drosophila melanogaster. The mechanisms by which PDF functions as a circadian peptide transmitter are not fully understood, however; in particular, nothing is known about the role of extracellular peptidases in terminating PDF signalling at synapses. In this study we show that PDF is susceptible to hydrolysis by neprilysin, an endopeptidase that is enriched in synaptic membranes of mammals and insects. Neprilysin cleaves PDF at the internal Ser7–Leu8 peptide bond to generate PDF1-7 and PDF8-18. Neither of these fragments were able to increase intracellular cAMP levels in HEK293 cells cotransfected with the Drosophila PDF receptor cDNA and a firefly luciferase reporter gene, confirming that such cleavage results in PDF inactivation. The Ser7–Leu8 peptide bond was also the principal cleavage site when PDF was incubated with membranes prepared from heads of adult Drosophila. This endopeptidase activity was inhibited by the neprilysin inhibitors phosphoramidon (IC_50, 0.15 µmol l^–1) and thiorphan (IC_50, 1.2 µmol l^–1). We propose that cleavage by a member of the Drosophila neprilysin family of endopeptidases is the most likely mechanism for inactivating synaptic PDF and that neprilysin might have an important role in regulating PDF signals within circadian neural circuits.

Key words: pigment dispersing factor, neprilysin, peptidase, neuropeptide, circadian rhythm

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				H. Meyer, M. Panz, M. Zmojdzian, K. Jagla, and A. Paululat Neprilysin 4, a novel endopeptidase from Drosophila melanogaster, displays distinct substrate specificities and exceptional solubility states J. Exp. Biol., November 15, 2009; 212(22): 3673 - 3683. [Abstract] [Full Text] [PDF]