title: Visualization of localized store-operated calcium entry in mouse astrocytes. Close proximity to the endoplasmic reticulum.
abstract: Unloading of endoplasmic reticulum (ER) Ca(2+) stores activates influx of extracellular Ca(2+) through 'store-operated' Ca(2+) channels (SOCs) in the plasma membrane (PM) of most cells, including astrocytes. A key unresolved issue concerning SOC function is their spatial relationship to ER Ca(2+) stores. Here, using high resolution imaging with the membrane-associated Ca(2+) indicator, FFP-18, it is shown that store-operated Ca(2+) entry (SOCE) in primary cultured mouse cortical astrocytes occurs at plasma membrane-ER junctions. In the absence of extracellular Ca(2+), depletion of ER Ca(2+) stores using cyclopiazonic acid, an ER Ca(2+)-ATPase inhibitor, and caffeine transiently increases the sub-plasma-membrane Ca(2+) concentration ([Ca(2+)](SPM)) within a restricted space between the plasma membrane and adjacent ER. Restoration of extracellular Ca(2+) causes localized Ca(2+) influx that first increases [Ca(2+)](SPM) in the same restricted regions and then, with a delay, in ER-free regions. Antisense knockdown of the TRPC1 gene, proposed to encode endogenous SOCs, markedly reduces SOCE measured with Fura-2. High resolution immunocytochemistry with anti-TRPC1 antibody reveals that these TRPC-encoded SOCs are confined to the PM microdomains adjacent to the underlying 'junctional' ER. Thus, Ca(2+) entry through TRPC-encoded SOCs is closely linked, not only functionally, but also structurally, to the ER Ca(2+) stores.
authors.affiliation: Department of Physiology, University of Maryland School of Medicine, 685 W. Baltimore Street, Baltimore, MD 21201, USA. vgolovin@umaryland.edu
authors.forename: Vera A
authors.initials: VA
authors.lastname: Golovina
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence / Q000379:methods*; D050052:TRPC Cation Channels
chemical_list: D015220:Calcium Channels; D005456:Fluorescent Dyes; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D002118:Calcium; D016257:Fura-2
references.citation: J Cell Biol. 1998 Jan 26;140(2):325-34
references.pmid: 9442108
references.citation: J Physiol. 1998 Jan 1;506 ( Pt 1):109-25
references.pmid: 9481676
references.citation: Cell. 1999 Oct 1;99(1):5-8
references.pmid: 10520988
references.citation: Neurology. 1965 Feb;15:132-40
references.pmid: 14275270
references.citation: J Cell Biol. 1976 Aug;70(2 pt 1):338-47
references.pmid: 939781
references.citation: Proc Natl Acad Sci U S A. 1999 Dec 21;96(26):14955-60
references.pmid: 10611319
references.citation: J Biol Chem. 2000 Feb 4;275(5):3403-11
references.pmid: 10652333
references.citation: Trends Neurosci. 2000 Apr;23(4):159-66
references.pmid: 10717675
references.citation: Glia. 2000 Jul;31(1):15-28
references.pmid: 10816603
references.citation: J Biol Chem. 2000 Aug 25;275(34):26158-63
references.pmid: 10851243
references.citation: Mol Cell. 2000 Aug;6(2):421-31
references.pmid: 10983988
references.citation: Circ Res. 2001 Jan 19;88(1):84-7
references.pmid: 11139478
references.citation: J Biomed Opt. 2001 Jan;6(1):6-13
references.pmid: 11178575
references.citation: Am J Physiol Heart Circ Physiol. 2001 Feb;280(2):H746-55
references.pmid: 11158974
references.citation: Nat Rev Neurosci. 2001 Jun;2(6):387-96
references.pmid: 11389472
references.citation: J Biol Chem. 2001 Jun 15;276(24):21303-10
references.pmid: 11290752
references.citation: Cell Calcium. 2003 Apr;33(4):283-92
references.pmid: 12618149
references.citation: J Neurosci. 2003 Jun 1;23(11):4737-45
references.pmid: 12805313
references.citation: Cell. 2003 Sep 19;114(6):777-89
references.pmid: 14505576
references.citation: J Biol Chem. 2003 Nov 7;278(45):44769-79
references.pmid: 12941956
references.citation: Cell Biol Int. 1997 Oct;21(10):655-63
references.pmid: 9693835
references.citation: Biochem Biophys Res Commun. 1998 Jul 30;248(3):679-83
references.pmid: 9703986
references.citation: Experientia. 1985 Jul 15;41(7):841-56
references.pmid: 3924650
references.citation: J Gen Physiol. 1988 Jul;92(1):1-26
references.pmid: 2459298
references.citation: J Histochem Cytochem. 1989 Jan;37(1):75-82
references.pmid: 2491754
references.citation: J Physiol. 1998 Dec 1;513 ( Pt 2):369-79
references.pmid: 9806989
references.citation: Trends Neurosci. 1999 May;22(5):208-15
references.pmid: 10322493
references.citation: J Physiol. 1999 Aug 1;518 ( Pt 3):815-24
references.pmid: 10420017
references.citation: J Biol Chem. 2004 Jan 23;279(4):2885-93
references.pmid: 14593108
references.citation: J Physiol. 2004 May 1;556(Pt 3):805-17
references.pmid: 14966303
references.citation: J Cell Biol. 2004 Aug 16;166(4):537-48
references.pmid: 15302852
references.citation: J Neurocytol. 1976 Feb;5(1):125-36
references.pmid: 1249590
references.citation: Trends Neurosci. 2001 Oct;24(10):602-8
references.pmid: 11576675
references.citation: J Neurochem. 2001 Oct;79(1):98-109
references.pmid: 11595762
references.citation: Sci STKE. 2001 Jul 10;2001(90):re1
references.pmid: 11752662
references.citation: FEBS Lett. 2002 Jan 16;510(3):189-95
references.pmid: 11801252
references.citation: Proc Natl Acad Sci U S A. 2002 May 28;99(11):7461-6
references.pmid: 12032305
references.citation: Eur J Neurosci. 2002 Jun;15(12):1891-8
references.pmid: 12099895
references.citation: J Physiol. 2002 Sep 1;543(Pt 2):455-64
references.pmid: 12205181
references.citation: Mol Hum Reprod. 2002 Oct;8(10):946-51
references.pmid: 12356946
references.citation: Nat Cell Biol. 2002 Nov;4(11):E263-72
references.pmid: 12415286
references.citation: Neuron. 2002 Dec 5;36(5):787-90
references.pmid: 12467583
references.citation: Am J Physiol Cell Physiol. 2003 Feb;284(2):C475-86
references.pmid: 12388076
references.citation: Glia. 2003 Mar;41(4):347-53
references.pmid: 12555202
references.citation: J Physiol. 2003 Mar 1;547(Pt 2):333-48
references.pmid: 12576497
references.citation: Science. 1990 Jan 26;247(4941):470-3
references.pmid: 1967852
references.citation: FEBS Lett. 1990 Apr 9;263(1):5-9
references.pmid: 2185036
references.citation: Cell Calcium. 1990 Nov-Dec;11(10):611-24
references.pmid: 1965707
references.citation: Glia. 1991;4(5):448-55
references.pmid: 1718862
references.citation: Nature. 1993 Aug 26;364(6440):809-14
references.pmid: 8355806
references.citation: J Biol Chem. 1994 Apr 1;269(13):10141-9
references.pmid: 8144515
references.citation: Trends Pharmacol Sci. 1995 Mar;16(3):98-105
references.pmid: 7792935
references.citation: J Biol Chem. 1995 Sep 22;270(38):22445-51
references.pmid: 7673232
references.citation: Biochem J. 1995 Nov 15;312 ( Pt 1):1-11
references.pmid: 7492298
references.citation: Biophys J. 1995 Nov;69(5):2112-24
references.pmid: 8580355
references.citation: Mol Cell Biochem. 1995 Aug-Sep;149-150:137-44
references.pmid: 8569723
references.citation: Proc Natl Acad Sci U S A. 1996 May 28;93(11):5368-73
references.pmid: 8643581
references.citation: Ann N Y Acad Sci. 1996 Apr 15;779:318-35
references.pmid: 8659845
references.citation: Pflugers Arch. 1996 Jun;432(2):286-92
references.pmid: 8662305
references.citation: J Neurosci Res. 1996 Nov 1;46(3):305-15
references.pmid: 8933369
references.citation: Cell Calcium. 1996 Apr;19(4):355-62
references.pmid: 8983856
references.citation: Proc Natl Acad Sci U S A. 1997 Mar 4;94(5):1800-5
references.pmid: 9050859
references.citation: Science. 1997 Mar 14;275(5306):1643-8
references.pmid: 9054358
references.citation: Curr Biol. 1997 Aug 1;7(8):599-602
references.pmid: 9259550
references.citation: J Neurosci. 1997 Oct 15;17(20):7817-30
references.pmid: 9315902
references.citation: Physiol Rev. 1997 Oct;77(4):901-30
references.pmid: 9354808