Enzyme or Coenzyme

Receptor Tyrosine Kinase-like Orphan Receptors

A family of cell surface receptors that were originally identified by their structural homology to neurotropic TYROSINE KINASES and referred to as orphan receptors because the associated ligand and signaling pathways were unknown. Evidence for the functionality of these proteins has been established by experiments showing that disruption of the orphan receptor genes results in developmental defects.