A phosphoproteomics approach to elucidate neuropeptide signal transduction controlling insect metamorphosis.
In insects, the neuropeptide prothoracicotropic hormone (PTTH) stimulates production of ecdysone (E) in the prothoracic glands (PGs). E is the precursor of the principal steroid hormone, 20-hydroxyecdysone (20E), that is responsible for eliciting molting and metamorphosis. In this study, we used quantitative phosphoproteomics to investigate signal transduction events initiated by PTTH. We identified Spook (CYP307A1), a suspected rate-limiting enzyme for E biosynthesis, and components of the mitogen-activated protein kinase (MAPK) pathway, as major phosphorylation targets of PTTH signaling. Further, proteins not previously linked to PTTH and ecdysone biosynthesis were identified as targets of PTTH signaling. These include proteins involved in signal transduction, endosomal trafficking, constituents of the cytoskeleton and regulators of transcription and translation. Our screen shows that PTTH likely stimulates E production by activation of Spook, an integral enzyme in the E biosynthetic pathway. This directly connects PTTH signaling to the pathway that produces E. A new mechanism for regulation of E biosynthesis in insects is proposed.
The Department of Science, Systems and Models, Roskilde University, 4000 Roskilde, Denmark. rewit004@umn.edu
Kim F
KF
Rewitz
Martin R
MR
Larsen
Anders
A
Lobner-Olesen
Robert
R
Rybczynski
Michael B
MB
O'Connor
Lawrence I
LI
Gilbert
D000595:Amino Acid Sequence; D000818:Animals; D004440:Ecdysone / Q000096:biosynthesis / Q000235:genetics; D007301:Insect Hormones / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018402:Manduca / Q000737:chemistry / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D008675:Metamorphosis, Biological; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D018978:Molting; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D040901:Proteomics / Q000379:methods*; D016415:Sequence Alignment; D015398:Signal Transduction
D007301:Insect Hormones; D019476:Insect Proteins; D010750:Phosphoproteins; D004440:Ecdysone; C009089:prothoracicotropic hormone; D020928:Mitogen-Activated Protein Kinases