Torso-Like Is a Component of the Hemolymph and Regulates the Insulin Signaling Pathway in Drosophila

Abstract

In Drosophila key developmental transitions are governed by the steroid hormone ecdysone.

Insulin-like signalling influences the coordination ofDrosophilalarval hemocyte number with body size

“…tsl Δ mutant animals have previously been reported to have a reduced growth rate and body size due to a disruption in the insulin-like signalling pathway (Henstridge et al 2018, Johnson et al 2013). Therefore, we questioned whether this could be contributing to the larval hemocyte number deficit.…”

“…Tsl is a member of the Membrane Attack Complex/ Perforin-like (MACPF) protein family, and has been shown to control a variety of developmental processes by modulating the activity of several different cell signalling pathways. These include terminal patterning in the early embryo via the Torso receptor (Stevens et al 1990), embryonic morphogenesis via Fog signalling (Johnson et al 2017), and larval growth via Insulin-like signalling (Johnson et al 2013, Henstridge et al 2018). Due to the latter role, tsl mutants have a reduced body size.…”

Insulin-Like Signalling Influences the Coordination of Larval Hemocyte Number with Body Size inDrosophila melanogaster

“…Finally, we show that both tsl and insulin-like signaling influence larval hemocyte numbers via their effect on larval growth. Tsl is produced by the prothoracic gland to promote growth, thus this is likely the source of Tsl for its role in the control of larval hemocyte expansion (Henstridge et al 2018). Tsl facilitates larval growth by promoting systemic insulin-like signaling and as such tsl mutants likely have reduced hemocyte numbers due to reduced levels of insulin-like signaling.…”

“…tsl mutant animals have previously been reported to have a reduced growth rate and body size due to a disruption in the insulin-like signaling pathway (Henstridge et al 2018, Johnson et al 2013. Therefore, we questioned whether this could be contributing to the larval hemocyte number deficit.…”

“…Tsl is a member of the Membrane Attack Complex/Perforin-like (MACPF) protein family, and has been shown to control a variety of developmental processes by modulating the activity of several different cell signaling pathways. These include terminal patterning in the early embryo via the Torso receptor (Stevens et al 1990), embryonic morphogenesis via Fog signaling (Johnson et al 2017), and both larval growth and developmental timing via Insulin-like signaling (Johnson et al 2013, Henstridge et al 2018. Due to the latter roles, tsl mutants have a reduced body size and a developmental delay.…”