Persephone in Insect Immunity

Question 1

What is Persephone and how is it activated?

Answer 1

Persephone is a serine protease that belongs to a danger pathway activated by abnormal proteolytic activities, and results in the activation of the Toll pathway. The Persephone pathway can be activated by the exogenous proteases of a range of different microorganisms, including Gram-negative bacteria. Persephone itself is an immune receptor able to sense a broad range of microbes through virulence factor activities rather than molecular patterns.

Question 2

Explain the Persephone signalling cascade.

Answer 2

Persephone has a unique region in the pro-domain of Persephone that functions as bait for exogenous proteases independently of their origin, type, or specificity. Cleavage in this bait region constitutes the first step of a sequential activation and licenses the subsequent maturation of Persephone to the endogenous cysteine cathepsin 266-29-p. Activated Persephone is then able to activate the Spaetzle-processing enzyme (SPE), after which activated SPE activates pro-Spaetzle to form active Spaetzle, which triggers the Toll pathway.