Practice question

Hedgehog pathway core components include secreted cholesterol-modified ligand Hedgehog, twelve-pass receptor Patched with sterol sensing domain, seven-pass transducer Smoothened homologous to Frizzled GPCR, transcription factor Gli/Ci with five zinc fingers, suppressor Sufu sequestering Gli, and Kif7 kinesin. Upon activation, Smoothened accumulates in primary cilium membrane blocking proteolytic cleavage of Gli into repressor GliR, generating activator GliA driving targets Patched, Hhip. LRP5/6 is single-pass Wnt co-receptor binding Wnt with Frizzled, recruiting Axin, stabilizing beta-catenin for TCF activation. LRP not involved in Hedgehog binding or transduction, distinguishing pathway specificity for patterning and growth.