[Term] id: PR:000000102 name: lefty protein def: "A TGF-beta-like cystine-knot cytokine that is an antagonist of nodal signaling. The nodal and lefty genes form positive and negative regulatory loops that resemble the reaction-diffusion system. As a pair, these genes control various events of vertebrate embryonic patterning, including left-right specification and mesoderm formation." [PRO:CNA] comment: Category=family. xref: PIRSF:PIRSF037402 is_a: PR:000000008 ! TGF-beta-like cystine-knot cytokine