title: NO-released zinc supports the simultaneous binding of Raf-1 and PKCγ cysteine-rich domains to HINT1 protein at the mu-opioid receptor.
abstract: In the brain, the mu-opioid receptor (MOR) activates neural nitric oxide synthase (nNOS) through the PI3K/Akt pathway. The resulting nitric oxide (NO) enhances the function of the glutamate N-methyl-d-aspartate receptor (NMDAR)/calcium and calmodulin-dependent serine/threonine kinase (CaMKII), which subsequently diminishes MOR signaling strength. Because the ERK1/2 cascade is implicated in opioid tolerance, we analyzed the role of morphine-generated NO in this negative regulation. We found that NO-released endogenous zinc ions recruit the Ras/Raf-1/ERK1/2 cassette to histidine triad nucleotide-binding protein 1 (HINT1). A-Raf and B-Raf showed little or no MOR association. The zinc ions bridge the Raf-1 cysteine-rich domain (CRD) with HINT1 at the MOR C-terminus. Morphine also recruits PKCγ via NO/zinc to the MOR-HINT1 complex. Both Raf-1 and PKCγ CRDs bind simultaneously to HINT1, enabling PKCγ to enhance Raf-1 function to intensify MEK/ERK1/2 activation. Thus, through attached HINT1, the MOR facilitates the cross-talk of two NO- and zinc-regulated signal-transduction pathways, PKC/Src and Raf-1/ERK1/2, implicated in the negative control of morphine effects. This study reveals new aspects of ERK1/2 regulation by the MOR without requiring the transactivation of a receptor tyrosine kinase.
authors.affiliation: CIBER Mental Health (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Rodríguez-Muñoz
authors.forename: Elena
authors.initials: E
authors.lastname: de la Torre-Madrid
authors.forename: Pilar
authors.initials: P
authors.lastname: Sánchez-Blázquez
authors.forename: Javier
authors.initials: J
authors.lastname: Garzón
mesh_terms: D000701:Analgesics, Opioid / Q000378:metabolism; D000818:Animals; D002614:Chelating Agents / Q000378:metabolism; D005029:Ethylenediamines / Q000378:metabolism; D008297:Male; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009020:Morphine / Q000378:metabolism; D009281:Naphthalenes / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D009574:Nitro Compounds / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism*; D017450:Receptors, Opioid, mu / Q000378:metabolism*; D026423:S-Nitroso-N-Acetylpenicillamine / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D015032:Zinc / Q000378:metabolism*
chemical_list: D000701:Analgesics, Opioid; D002614:Chelating Agents; D005029:Ethylenediamines; C489275:Hint1 protein, mouse; D009281:Naphthalenes; D009419:Nerve Tissue Proteins; D020030:Nitric Oxide Donors; D009574:Nitro Compounds; D017450:Receptors, Opioid, mu; C061465:calphostin complex; D009569:Nitric Oxide; D009020:Morphine; D026423:S-Nitroso-N-Acetylpenicillamine; C061872:FK 409; D052248:Nitric Oxide Synthase Type I; C087857:protein kinase C gamma; D019908:Proto-Oncogene Proteins c-raf; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D015032:Zinc; C044387:N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine