The protein Sonic Hedgehog (SHH) plays a role in specifying the identity of digits (such as fingers and toes) in mammals. Several digits arise directly from cells that both express and respond to secrete SHH. What type of signaling would this be considered

Autocrine signaling

Explanation:

In autocrine signaling,signal acts on same cells which produce them

Sonic Hedgehog helps in cell growth and development Hedgehog signaling pathway plays an essential role during vertebrate embryonic development Sonic hedgehog has particularly marked roles in nervous system cell type specification and limbs patterningActivation of sonic hedgehog pathway can happen in two major ways:Canonical signaling: by ligand-dependent interaction or through receptor-induced signaling Non-canonical signaling:when there’s a mechanism of activation downstream of smoothened The sonic hedgehog canonical signaling occurs when the glycoprotein sonic hedgehog binds and inactivates the 12-transmembrane protein Patched In the lack of the ligand sonic hedgehog, the activity of the 7-transmembrane protein smoothened is inhibited by patched so sonic hedgehog protein binding patched regulates smoothened activity The non–canonical activation occurs through Gli-independent mechanisms and it can be of two typesType I which modulates Ca2+ and actin cytoskeletonWhen sonic hedgehog binds the receptor patched, smoothened is no longer inhibited and couple Gi proteins (G) and small GTPases RhoA and Rac1 activatedType II is the one which is independent on smoothenedWhen smoothened binds patched, the interaction of patched with cyclin B1 is disrupted, leading to an increase in cell proliferation and survival