False positives in MALDI-TOF detection of ER{beta} in mitochondria
- Department of Biosciences and Nutrition, Karolinska Institutet/NOVUM, Haelsovaegen 7, S-141 86 Huddinge (Sweden)
Recently, Yang et al. reported that estrogen receptor beta (ER{beta}) is a mitochondrial protein rather than a nuclear receptor. Because this claim would lead to a significant change in our understanding of estrogen signaling, we have attempted to reproduce the MALDI-TOF data of Yang et al. We separated proteins extracted from mouse liver mitochondria by SDS-PAGE and analysed a gel band covering the molecular weight range of 50-65 kDa by MALDI-TOF/TOF. Analysis of the data with the MASCOT database algorithm provided no evidence for the presence of ER{beta} in the mitochondria. If we search (as the authors did) with only the peptide masses which match to tryptic fragments of ER{beta}, ER{beta} is identified with a significant score of 69. However, fragmentation of these peptides shows that they are not from ER{beta}. Our conclusion is that ER{beta} cannot be identified by MALDI-TOF from a mixture of mitochondrial proteins resolved on SDS-PAGE.
- OSTI ID:
- 20798940
- Journal Information:
- Biochemical and Biophysical Research Communications, Journal Name: Biochemical and Biophysical Research Communications Journal Issue: 3 Vol. 343; ISSN BBRCA9; ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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