Description
Bursicon is a heterodimer glycoprotein hormone that is
involved in the regulation of ecdysis and postecdysis processes
associated with expansion, tanning, and sclerotization of the
cuticle as well as feeding behavior in insects and innate
immunity in crustaceans.
Properties
burs, Mr 15,678; pburs, Mr 13,059.
Biological functions
In D. melanogaster, bursicon controls cuticle sclerotization
and melanization.In D. melanogaster, B. mori, and
the beetle Tribolium castaneum, it is necessary for the
expansion and hardening of the wings.The expansion
of wings requires bursicon-induced extensibility of the
wing cuticle, as demonstrated in the moth M. sexta.In
D. melanogaster, burs-β is an important signal for controlling
ecdysis behavior.In the crab C. sapidus, bursicon
controls the deposition and thickening of the new cuticle
as well as the granulation of hemocytes.In both Procambarus
clarkii and D. melanogaster, bursicon homodimers
induce innate immunity by altering antimicrobial peptides
via Relish.Besides, burs-α in D. melanogaster
binds to its neuronal receptor DLgr2, eventually regulating
organismal resistance to metabolic challenges
through Adipokinetic hormone signaling.
Regulation of synthesis and release
In the larvae of D. melanogaster, bursicon appears to be
released in two temporal waves, the first prior to the
onset of ecdysis and the second immediately after ecdysis
onset. In adults, bursicon is also released in two consecutive
waves. Initial bursicon secretion from two neurons
in the SG subsequently elicits its secondary release from a
cluster of abdominal neurons, which controls the expansion,
hardening, and pigmentation of the cuticle and
wings.In Neocaridina heteropoda, the abdominal ganglion
is the main neurohemal release site of bursicon.
