Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP), a member of the secretin/glucagon/vasoactive intestinal peptide family expressed throughout the nervous system, binds to the PACAP-specific G-protein-coupled receptor family members to promote both neuronal differentiation and survival. Although the PACAP receptor is known to activate its effector protein, adenylate cyclase (AC), and thus enhance cAMP generation, the molecular mechanism utilized by the receptor to activate AC is lacking. Here, we show that PACAP induces neurite outgrowth in PC12 cells by induction of translocation of the PACAP type 1 receptor (PAC1R) into caveolin-enriched Triton X-100-insoluble microdomains, leading to stronger PAC1R-AC interaction and elevated cAMP production. Moreover, we demonstrate that translocation of PAC1R is blocked by various treatments that selectively disrupt caveolae. As a result, intracellular cAMP level is decreased and consequently the PACAP-induced neurite outgrowth retarded. In contrast, addition of exogenous ganglioside GM1 to the cells shows the opposite effects. These results therefore identify the PACAP-induced translocation of its G-protein-coupled receptor into caveolae, where both AC and the regulating G-proteins reside, as the key molecular event in activating AC and inducing cAMP-mediated differentiation of PC12 cells.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenylyl Cyclases / metabolism
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Animals
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Caveolae / drug effects
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Caveolae / metabolism*
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Cell Differentiation / drug effects
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Cell Differentiation / physiology
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Central Nervous System / embryology
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Central Nervous System / growth & development
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Central Nervous System / metabolism
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Cyclic AMP / biosynthesis*
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Enzyme Activation / drug effects
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Enzyme Activation / physiology
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G(M1) Ganglioside / metabolism
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G(M1) Ganglioside / pharmacology
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Membrane Microdomains / drug effects
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Membrane Microdomains / metabolism*
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Neurites / drug effects
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Neurites / metabolism*
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PC12 Cells
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Pituitary Adenylate Cyclase-Activating Polypeptide / metabolism*
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Protein Transport / drug effects
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Protein Transport / physiology
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Rats
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Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide / metabolism*
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Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I / drug effects
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Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I / metabolism
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Signal Transduction / drug effects
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Signal Transduction / physiology
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Up-Regulation / drug effects
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Up-Regulation / physiology
Substances
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Pituitary Adenylate Cyclase-Activating Polypeptide
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Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
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Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I
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G(M1) Ganglioside
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Cyclic AMP
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Adenylyl Cyclases