title: Transport of receptors, receptor signaling complexes and ion channels via neuropeptide-secretory vesicles.
abstract: Stimulus-induced exocytosis of large dense-core vesicles (LDCVs) leads to discharge of neuropeptides and fusion of LDCV membranes with the plasma membrane. However, the contribution of LDCVs to the properties of the neuronal membrane remains largely unclear. The present study found that LDCVs were associated with multiple receptors, channels and signaling molecules, suggesting that neuronal sensitivity is modulated by an LDCV-mediated mechanism. Liquid chromatography-mass spectrometry combined with immunoblotting of subcellular fractions identified 298 proteins in LDCV membranes purified from the dorsal spinal cord, including G-protein-coupled receptors, G-proteins and other signaling molecules, ion channels and trafficking-related proteins. Morphological assays showed that δ-opioid receptor 1 (DOR1), β2 adrenergic receptor (AR), G(αi2), voltage-gated calcium channel α2δ1 subunit and P2X purinoceptor 2 were localized in substance P (SP)-positive LDCVs in small-diameter dorsal root ganglion neurons, whereas β1 AR, Wnt receptor frizzled 8 and dishevelled 1 were present in SP-negative LDCVs. Furthermore, DOR1/G(αi2)/G(β1γ5)/phospholipase C β2 complexes were associated with LDCVs. Blockade of the DOR1/G(αi2) interaction largely abolished the LDCV localization of G(αi2) and impaired stimulation-induced surface expression of G(αi2). Thus, LDCVs serve as carriers of receptors, ion channels and preassembled receptor signaling complexes, enabling a rapid, activity-dependent modulation of neuronal sensitivity.
authors.affiliation: Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhao
authors.forename: Hai-Bo
authors.initials: HB
authors.lastname: Wang
authors.forename: Ying-Jin
authors.initials: YJ
authors.lastname: Lu
authors.forename: Jian-Wen
authors.initials: JW
authors.lastname: Hu
authors.forename: Lan
authors.initials: L
authors.lastname: Bao
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001692:Biological Transport; D051960:GTP-Binding Protein alpha Subunit, Gi2 / Q000378:metabolism; D044387:GTP-Binding Protein beta Subunits / Q000378:metabolism; D005727:Ganglia, Spinal / Q000378:metabolism / Q000648:ultrastructure; D007473:Ion Channels / Q000378:metabolism*; D051379:Mice; D009479:Neuropeptides / Q000378:metabolism*; D016716:PC12 Cells; D054799:Phospholipase C beta / Q000378:metabolism; D051381:Rats; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D022142:Secretory Vesicles / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D044387:GTP-Binding Protein beta Subunits; D007473:Ion Channels; D009479:Neuropeptides; D043562:Receptors, G-Protein-Coupled; D054799:Phospholipase C beta; D051960:GTP-Binding Protein alpha Subunit, Gi2