RGD Reference Report - Plasma membrane-cytoskeleton-endoplasmic reticulum complexes in neurons and astrocytes. - Rat Genome Database

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Plasma membrane-cytoskeleton-endoplasmic reticulum complexes in neurons and astrocytes.

Authors: Lencesova, L  O'Neill, A  Resneck, WG  Bloch, RJ  Blaustein, MP 
Citation: Lencesova L, etal., J Biol Chem. 2004 Jan 23;279(4):2885-93. Epub 2003 Oct 30.
RGD ID: 6767300
Pubmed: PMID:14593108   (View Abstract at PubMed)
DOI: DOI:10.1074/jbc.M310365200   (Journal Full-text)

The possibility that certain integral plasma membrane (PM) proteins involved in Ca(2+) homeostasis form junctional units with adjacent endoplasmic reticulum (ER) in neurons and glia was explored using immunoprecipitation and immunocytochemistry. Rat brain membranes were solubilized with the mild, non-ionic detergent, IGEPAL CA-630. Na(+)/Ca(2+) exchanger type 1 (NCX1), a key PM Ca(2+) transporter, was immunoprecipitated from the detergent-soluble fraction. Several abundant PM proteins co-immunoprecipitated with NCX1, including the alpha2 and alpha3 isoforms of the Na(+) pump catalytic (alpha) subunit, and the alpha2 subunit of the dihydropyridine receptor. The adaptor protein, ankyrin 2 (Ank 2), and the cytoskeletal proteins, alpha-fodrin and beta-spectrin, also selectively co-immunoprecipitated with NCX1, as did the ER proteins, Ca(2+) pump type 2 (SERCA 2), and inositol-trisphosphate receptor type 1 (IP(3)R-1). In contrast, a number of other abundant PMs, adaptors, and cytoskeletal proteins did not co-immunoprecipitate with NCX1, including the Na(+) pump alpha1 isoform, PM Ca(2+) pump type 1 (PMCA1), beta-fodrin, and Ank 3. In reciprocal experiments, immunoprecipitation with antibodies to the Na(+) pump alpha2 and alpha3 isoforms, but not alpha1, co-immunoprecipitated NCX1; the antibodies to alpha1 did, however, co-immunoprecipitate PMCA1. Antibodies to Ank 2, alpha-fodrin, beta-spectrin and IP(3)R-1 all co-immunoprecipitated NCX1. Immunocytochemistry revealed partial co-localization of beta-spectrin with NCX1, Na(+) pump alpha3, and IP(3)R-1 in neurons and of alpha-fodrin with NCX1 and SERCA2 in astrocytes. The data support the idea that in neurons and glia PM microdomains containing NCX1 and Na(+) pumps with alpha2 or alpha3 subunits form Ca(2+) signaling complexes with underlying ER containing SERCA2 and IP(3)R-1. These PM and ER components appear to be linked through the cytoskeletal spectrin network, to which they are probably tethered by Ank 2.



Gene Ontology Annotations    Click to see Annotation Detail View

Molecular Function

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Ank2Ratprotein binding  IPISlc8a1 (Rattus norvegicus) RGD 
Slc8a1Ratprotein binding  IPIAnk2 (Rattus norvegicus) RGD 

Objects Annotated

Genes (Rattus norvegicus)
Ank2  (ankyrin 2)
Slc8a1  (solute carrier family 8 member A1)


Additional Information