This family consists of the pedibin and Hym-346 signalling peptides. These two peptides have been isolated from Hydra vulgaris and Hydra magnipapillata. Experiments have indicated that both cause a reduction in the positional value gradient, the principle patterning process governing the maintenance of form in the adult hydra. The peptides cause an increase in the rate of foot regeneration following bisection of the body column. Thus both play important signalling roles in patterning processes in cnidaria and maybe in more complex metazoans [1].

1: The novel signal peptides, pedibin and Hym-346, lower positional value thereby enhancing foot formation in hydra. Grens A, Shimizu H, Hoffmeister SA, Bode HR, Fujisawa T; Development 1999;126:517-524. PMID:9876180

2: Identification of an astacin matrix metalloprotease as target gene for Hydra foot activator peptides. Kumpfmuller G, Rybakine V, Takahashi T, Fujisawa T, Bosch TC; Dev Genes Evol. 1999;209:601-607. PMID:10552301

3: Control of foot differentiation in Hydra: in vitro evidence that the NK-2 homeobox factor CnNK-2 autoregulates its own expression and uses pedibin as target gene. Thomsen S, Till A, Wittlieb J, Beetz C, Khalturin K, Bosch TC; Mech Dev. 2004;121:195-204. PMID:15037320

4: Peptide signaling in Hydra. Fujisawa T, Hayakawa E; Int J Dev Biol. 2012; [Epub ahead of print] PMID:22689368