Journal article
Localization and function of the brain excitatory amino acid transporter type 1 in cardiac mitochondria
Journal of molecular and cellular cardiology, Vol.37(1), pp.33-41
2004
DOI: 10.1016/j.yjmcc.2004.04.008
PMID: 15242733
Abstract
Glutamate is the only amino acid extracted by healthy myocardium in net amounts, with uptake further increased during hypoxic or ischemic conditions. Glutamate supplementation provides cardioprotection from hypoxic and reperfusion injury through several metabolic pathways that depend upon adequate transport of glutamate into the mitochondria. Glutamate transport across the inner mitochondrial membrane is a key component of the malate/aspartate shuttle. Glutamate transport in the brain has been well characterized since the discovery of the excitatory amino acid transporter (EAAT) family. We hypothesize that a protein similar to EAAT1 found in brain may function as a glutamate transporter in cardiac mitochondria. Rat heart total RNA was screened by reverse transcriptase-polymerase chain reaction with an array of primer pairs derived from the rat brain EAAT1 cDNA sequence, yielding a 3786-bp cDNA comprising a 1638-bp open reading frame identical to rat brain EAAT1 with flanking 5′- and 3′-untranslated regions. Northern blot analysis confirmed a 4-kb mRNA product in rat heart and brain, with greater abundance in brain. A protein of the predicted approximate 60-kD size was recognized in myocardial lysates by an anti-EAAT1 polyclonal antibody produced against an amino-terminal peptide from human EAAT1. The protein enriched in rat heart mitochondria by immunoblot, co-localized with the mitochondrial protein cytochrome
c by immunohistochemistry, and further localized to the inner mitochondrial membrane upon digitonin fractionation of the mitochondria. In myocytes overexpressing EAAT1, activity of the malate/aspartate shuttle increased by 33% compared to non-transfected cells (
P = 0.004). These data indicate that EAAT1 is expressed in myocardial mitochondria, and functions in the malate/aspartate shuttle, suggesting a role for EAAT1 in myocardial glutamate metabolism.
Details
- Title: Subtitle
- Localization and function of the brain excitatory amino acid transporter type 1 in cardiac mitochondria
- Creators
- J.Carter RalpheJeffrey L SegarBrian C SchutteThomas D Scholz
- Resource Type
- Journal article
- Publication Details
- Journal of molecular and cellular cardiology, Vol.37(1), pp.33-41
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/j.yjmcc.2004.04.008
- PMID
- 15242733
- ISSN
- 0022-2828
- eISSN
- 1095-8584
- Language
- English
- Date published
- 2004
- Academic Unit
- Cardiology; Stead Family Department of Pediatrics; Fraternal Order of Eagles Diabetes Research Center; Child and Community Health
- Record Identifier
- 9984093362702771
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