RESUMEN
The gene product of ocular albinism 1 (OA1)/G-protein-coupled receptor (GPR)143 is a receptor for L-3,4-dihydroxyphenylanine (l-DOPA), the most effective agent for Parkinson's disease. When overexpressed, human wild-type GPR143, but not its mutants, inhibits neurite outgrowth in PC12 cells. We investigated the downstream signaling pathway for GPR143-induced inhibition of neurite outgrowth. Nifedipine restored GPR143-induced neurite outgrowth inhibition to the level of control transfectant but did not affect outgrowth in GPR143-knockdown cells. Cilnidipine and flunarizine also suppressed the GPR143-induced inhibition, but their effects at higher concentrations still occurred even in GPR143-knockdown cells. These results suggest that GPR143 regulates neurite outgrowth via L-type calcium channel(s).
Asunto(s)
Canales de Calcio Tipo L , Proyección Neuronal , Nifedipino , Receptores Acoplados a Proteínas G , Células PC12 , Animales , Ratas , Canales de Calcio Tipo L/metabolismo , Canales de Calcio Tipo L/genética , Nifedipino/farmacología , Proyección Neuronal/efectos de los fármacos , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/fisiología , Humanos , Proteínas del Ojo/genética , Proteínas del Ojo/metabolismo , Proteínas del Ojo/farmacología , Flunarizina/farmacología , Transducción de Señal/efectos de los fármacos , Levodopa/farmacología , Técnicas de Silenciamiento del Gen , Neuritas/efectos de los fármacos , Bloqueadores de los Canales de Calcio/farmacología , Glicoproteínas de MembranaRESUMEN
Methylphenidate (MPH) and methamphetamine (METH) are the current treatments of choice for attention deficit/hyperactivity disorder. We previously reported that METH induces the release of dopamine (DA) and of the neurotransmitter candidate L-3,4-dihydroxyphenylalanine (L-DOPA). In contrast, we here found that MPH increased the DA release while it did not affect the L-DOPA release from the dorsolateral striatum. Nevertheless, MPH-induced hyperlocomotion was reduced in Gpr143 (L-DOPA receptor) gene-deficient (Gpr143-/y) mice. The rewarding effect and increased c-fos expression induced by MPH were also attenuated in Gpr143-/y mice. Together, these findings suggest that GPR143 is involved in the acute and chronic actions of MPH.
Asunto(s)
Estimulantes del Sistema Nervioso Central , Metanfetamina , Metilfenidato , Ratones , Animales , Metilfenidato/farmacología , Levodopa/farmacología , Receptores de Neurotransmisores , Dopamina/metabolismo , Metanfetamina/farmacología , Estimulantes del Sistema Nervioso Central/farmacologíaRESUMEN
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein binds to the cellular receptor-angiotensin-converting enzyme-2 (ACE2) as the first step in viral cell entry. SARS-CoV-2 spike protein expression in the ACE2-expressing cell surface induces cell-cell membrane fusion, thus forming syncytia. To exert its fusogenic activity, the spike protein is typically processed at a specific site (the S1/S2 site) by cellular proteases such as furin. The C488 residue, located at the spike-ACE2 interacting surface, is critical for the fusogenic and infectious roles of the SARS-CoV-2 spike protein. We have demonstrated that the C488 residue of the spike protein is involved in subcellular targeting and S1/S2 processing. C488 mutant spike localization to the Golgi apparatus and cell surface were impaired. Consequently, the S1/S2 processing of the spike protein, probed by anti-Ser-686-cleaved spike antibody, markedly decreased in C488 mutant spike proteins. Moreover, brefeldin-A-mediated endoplasmic-reticulum-to-Golgi traffic suppression also suppressed spike protein S1/S2 processing. As brefeldin A treatment and C488 mutation inhibited S1/S2 processing and syncytia formation, the C488 residue of spike protein is required for functional spike protein processing.