Zeta Opioid Receptor: Proteins and Enzymes

Zeta Opioid Receptor is the receptor for opioid growth factor (OGF), also known as Met-enkephalin. Met-enkephalin (met-Enk) is an opioid peptide that acts via three main subtypes of receptors referred to as mu, delta and zeta receptors. The first two receptor subtypes mediate the classic opioid effects of met-Enk, wheras zeta-receptors are reported to be involved in the non-opioid actions of the peptide. OGF (Met-enkephalin)is an inhibitory peptide that modulates cell proliferation and tissue organization during development, cellular renewal, cancer, wound healing, and angiogenesis. The encoded unbound receptor for OGF has been localized to the outer nuclear envelope, where it binds OGF and is translocated into the nucleus. It has been found that the progression of some tumours is associated with the down regulation of opioid growth factor receptor expression.