Molecular model of RANKL (receptor activator of nuclear factor kappa B ligand) protein, composed of oxygen (red), nitrogen (blue), and carbon (green). A cytokine, it is also known as TNF-related activation-induced cytokine (TRANCE), osteoprotegerin ligand (OPGL), osteoclast differentiation factor (ODF), and osteoclastogenesis inhibitory factor (OCIF).