title: β-Adrenergic receptors activate exchange protein directly activated by cAMP (Epac), translocate Munc13-1, and enhance the Rab3A-RIM1α interaction to potentiate glutamate release at cerebrocortical nerve terminals.
abstract: The adenylyl cyclase activator forskolin facilitates synaptic transmission presynaptically via cAMP-dependent protein kinase (PKA). In addition, cAMP also increases glutamate release via PKA-independent mechanisms, although the downstream presynaptic targets remain largely unknown. Here, we describe the isolation of a PKA-independent component of glutamate release in cerebrocortical nerve terminals after blocking Na(+) channels with tetrodotoxin. We found that 8-pCPT-2'-O-Me-cAMP, a specific activator of the exchange protein directly activated by cAMP (Epac), mimicked and occluded forskolin-induced potentiation of glutamate release. This Epac-mediated increase in glutamate release was dependent on phospholipase C, and it increased the hydrolysis of phosphatidylinositol 4,5-bisphosphate. Moreover, the potentiation of glutamate release by Epac was independent of protein kinase C, although it was attenuated by the diacylglycerol-binding site antagonist calphostin C. Epac activation translocated the active zone protein Munc13-1 from soluble to particulate fractions; it increased the association between Rab3A and RIM1α and redistributed synaptic vesicles closer to the presynaptic membrane. Furthermore, these responses were mimicked by the β-adrenergic receptor (βAR) agonist isoproterenol, consistent with the immunoelectron microscopy and immunocytochemical data demonstrating presynaptic expression of βARs in a subset of glutamatergic synapses in the cerebral cortex. Based on these findings, we conclude that βARs couple to a cAMP/Epac/PLC/Munc13/Rab3/RIM-dependent pathway to enhance glutamate release at cerebrocortical nerve terminals.
authors.affiliation: From the Departamento de Bioquímica, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Jose J
authors.initials: JJ
authors.lastname: Ferrero
authors.forename: Ana M
authors.initials: AM
authors.lastname: Alvarez
authors.forename: Jorge
authors.initials: J
authors.lastname: Ramírez-Franco
authors.forename: María C
authors.initials: MC
authors.lastname: Godino
authors.forename: David
authors.initials: D
authors.lastname: Bartolomé-Martín
authors.forename: Carolina
authors.initials: C
authors.lastname: Aguado
authors.forename: Magdalena
authors.initials: M
authors.lastname: Torres
authors.forename: Rafael
authors.initials: R
authors.lastname: Luján
authors.forename: Francisco
authors.initials: F
authors.lastname: Ciruela
authors.forename: José
authors.initials: J
authors.lastname: Sánchez-Prieto
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D051379:Mice; D009281:Naphthalenes / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020826:rab3A GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000276:Adjuvants, Immunologic; D000318:Adrenergic beta-Agonists; D004791:Enzyme Inhibitors; C482601:Epac protein, mouse; D020662:Guanine Nucleotide Exchange Factors; D009281:Naphthalenes; D009419:Nerve Tissue Proteins; D011943:Receptors, Adrenergic, beta; C491490:Rims1 protein, mouse; C503321:Unc13a protein, mouse; D005576:Colforsin; D018698:Glutamic Acid; D000242:Cyclic AMP; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D020826:rab3A GTP-Binding Protein; C058819:calphostin C; D007545:Isoproterenol
keywords: Cyclic AMP (cAMP); Epac Proteins; G Protein-coupled Receptors (GPCR); Munc13–1; Neurotransmitter Release; Phospholipase C; RIM1α; Rab3A; Synaptosomes
references.citation: Brain Res. 1989 Jul 31;493(2):331-47
references.pmid: 2569914
references.citation: Annu Rev Cell Biol. 1990;6:433-60
references.pmid: 1980418
references.citation: Neurosignals. 2009;17(1):5-22
references.pmid: 18948702
references.citation: J Biol Chem. 1995 Mar 31;270(13):7750-6
references.pmid: 7706324
references.citation: Nature. 1994 Jun 9;369(6480):493-7
references.pmid: 7911226
references.citation: Nature. 1983 Mar 31-Apr 6;302(5907):432-4
references.pmid: 6300681
references.citation: J Neurosci. 2008 Aug 6;28(32):7991-8002
references.pmid: 18685024
references.citation: Nat Cell Biol. 2001 Apr;3(4):331-8
references.pmid: 11283605
references.citation: J Biol Chem. 2010 Jun 4;285(23):17907-17
references.pmid: 20375012
references.citation: Anal Biochem. 2006 Nov 1;358(1):126-35
references.pmid: 16965760
references.citation: Cell. 2003 Oct 3;115(1):49-60
references.pmid: 14532002
references.citation: Trends Biochem Sci. 2006 Dec;31(12):680-6
references.pmid: 17084085
references.citation: J Neurosci. 1996 Feb 1;16(3):1026-33
references.pmid: 8558230
references.citation: Islets. 2011 May-Jun;3(3):121-8
references.pmid: 21478675
references.citation: Endocrinology. 2012 Feb;153(2):574-82
references.pmid: 22147008
references.citation: J Neurosci. 2004 Jun 2;24(22):5202-8
references.pmid: 15175390
references.citation: Neurosci Lett. 1991 May 13;126(1):41-4
references.pmid: 1866083
references.citation: J Biol Chem. 1996 Nov 29;271(48):30554-60
references.pmid: 8940026
references.citation: J Neurosci. 2007 Jan 3;27(1):212-9
references.pmid: 17202488
references.citation: EMBO J. 2005 Aug 17;24(16):2839-50
references.pmid: 16052212
references.citation: J Biol Chem. 2003 Jun 27;278(26):23955-62
references.pmid: 12692128
references.citation: Nat Neurosci. 2004 Dec;7(12):1296-8
references.pmid: 15543142
references.citation: Neuron. 2002 Jan 31;33(3):411-24
references.pmid: 11832228
references.citation: Science. 1998 Dec 18;282(5397):2275-9
references.pmid: 9856955
references.citation: J Biol Chem. 2001 Dec 7;276(49):46046-53
references.pmid: 11598134
references.citation: Science. 2009 Jul 31;325(5940):607-10
references.pmid: 19644119
references.citation: J Neurosci. 1994 Jan;14(1):310-7
references.pmid: 7506766
references.citation: J Biol Chem. 2000 Jun 30;275(26):20033-44
references.pmid: 10748113
references.citation: Neuron. 1998 Jul;21(1):123-36
references.pmid: 9697857
references.citation: Genomics. 2003 Feb;81(2):126-37
references.pmid: 12620390
references.citation: Nature. 2002 Jan 17;415(6869):327-30
references.pmid: 11797010
references.citation: Nature. 1997 Aug 7;388(6642):593-8
references.pmid: 9252191
references.citation: Nature. 1995 Jun 22;375(6533):645-53
references.pmid: 7791897
references.citation: Nat Cell Biol. 2000 Nov;2(11):805-11
references.pmid: 11056535
references.citation: Eur J Neurosci. 1996 Jul;8(7):1488-500
references.pmid: 8758956
references.citation: J Neurochem. 2011 Feb;116(4):476-85
references.pmid: 21143597
references.citation: J Cell Sci. 2002 Dec 1;115(Pt 23):4399-411
references.pmid: 12414987
references.citation: J Biol Chem. 1993 Dec 25;268(36):27355-62
references.pmid: 8262976
references.citation: Cereb Cortex. 2008 Jul;18(7):1506-20
references.pmid: 17965126
references.citation: J Biol Chem. 2002 Apr 19;277(16):14092-101
references.pmid: 11825890
references.citation: Annu Rev Neurosci. 1998;21:75-95
references.pmid: 9530492
references.citation: J Biol Chem. 2009 Sep 11;284(37):24825-39
references.pmid: 19546222
references.citation: J Neurosci. 2006 Dec 13;26(50):13054-66
references.pmid: 17167095
references.citation: Biochemistry. 2005 Feb 1;44(4):1089-96
references.pmid: 15667202
references.citation: EMBO J. 2010 Feb 3;29(3):680-91
references.pmid: 20010694
references.citation: J Neurosci. 1995 Mar;15(3 Pt 2):2385-95
references.pmid: 7891174
references.citation: J Neurochem. 2003 Dec;87(5):1101-11
references.pmid: 14622090
references.citation: J Neurosci. 2008 Aug 13;28(33):8257-67
references.pmid: 18701688
references.citation: Proc Natl Acad Sci U S A. 2001 Jan 2;98(1):331-6
references.pmid: 11134533
references.citation: J Biol Chem. 1995 Oct 20;270(42):25273-80
references.pmid: 7559667
references.citation: Science. 1994 Sep 23;265(5180):1878-82
references.pmid: 7916482
references.citation: J Neurosci. 2005 Jan 5;25(1):208-14
references.pmid: 15634783
references.citation: Synapse. 2009 Apr;63(4):269-81
references.pmid: 19116948
references.citation: Nat Rev Mol Cell Biol. 2001 Feb;2(2):107-17
references.pmid: 11252952
references.citation: Cell. 2002 Jan 11;108(1):121-33
references.pmid: 11792326
references.citation: Nat Cell Biol. 2001 Nov;3(11):1020-4
references.pmid: 11715024
references.citation: Protein Sci. 1997 Feb;6(2):477-80
references.pmid: 9041654
references.citation: Nature. 1999 Jul 29;400(6743):457-61
references.pmid: 10440375
references.citation: Neuron. 2011 Jan 27;69(2):317-31
references.pmid: 21262469
references.citation: Neuron. 2009 Dec 10;64(5):663-77
references.pmid: 20005823
references.citation: Nature. 2002 Jan 17;415(6869):321-6
references.pmid: 11797009
references.citation: Mol Biol Cell. 2001 Oct;12(10):3095-102
references.pmid: 11598194
references.citation: Mol Pharmacol. 2006 Mar;69(3):846-56
references.pmid: 16306229
references.citation: Nat Neurosci. 1999 Nov;2(11):965-71
references.pmid: 10526334
references.citation: Nat Neurosci. 2001 Oct;4(10):997-1005
references.pmid: 11559854
references.citation: Nature. 1982 Oct 14;299(5884):636-8
references.pmid: 6289127
references.citation: Neuron. 2004 Jun 24;42(6):889-96
references.pmid: 15207234
references.citation: J Neurosci. 1995 Feb;15(2):1249-60
references.pmid: 7869096
references.citation: EMBO J. 1995 Jul 3;14(13):3036-44
references.pmid: 7621818
references.citation: Neuron. 2012 Feb 23;73(4):774-88
references.pmid: 22365550
references.citation: Cell. 2011 Jan 21;144(2):282-95
references.pmid: 21241895