Differential expression of cardiac mitochondrial proteins.
Mitochondria were isolated from whole hearts of Dahl salt sensitive (SS) and chromosome 13 consomic control (SS.13BN/Mcwi) rats using a mechanical homogenization process followed by density centrifugation. The proteins present in the two mitochondria preparations were quantified; equal amounts of protein from each sample were taken and trypsinized in the presence of either 16O or 18O before pooling. Incorporation of one or two 18O atoms at the C-terminus of the peptide cleaved by trypsin allows the distinction between the two samples. The proteins were identified by automated MS/MS sequencing and relative amounts of each protein assessed by comparison of the intensities of the constituent peptides. Relative quantification was performed using the ZoomQuant (v1.24) software. Nine proteins were found to be differentially expressed. Electron transfer flavoprotein alpha (P13803, ETFA) protein expression was two-fold lower in the SS compared to the SS.13BN. This was confirmed by Western blot and 2-DE gel quantification. Potential functional implications of this differential expression include an impaired capacity of the heart to oxidize fatty acids in the SS strain compared to the control. Mathematical modeling of mitochondrial electron transport predicted that the observed change in ETFA expression may result in decreased activity of the electron transport chain.
Smith
Julia R
JR
Biotechnology Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Matus
Isaac R
IR
Beard
Daniel A
DA
Greene
Andrew S
AS
D000595:Amino Acid Sequence; D000818:Animals; D008929:Mitochondria, Heart / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010103:Oxygen Isotopes / Q000737:chemistry; D020543:Proteome / Q000378:metabolism*; D051381:Rats; D020303:Rats, Inbred Dahl; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry
D024101:Mitochondrial Proteins; D010103:Oxygen Isotopes; D020543:Proteome