RRC ID 21153
Author Chenevert J, Pruliere G, Ishii H, Sardet C, Nishikata T.
Title Purification of mitochondrial proteins HSP60 and ATP synthase from ascidian eggs: implications for antibody specificity.
Journal PLoS ONE
Abstract Use of antibodies is a cornerstone of biological studies and it is important to identify the recognized protein with certainty. Generally an antibody is considered specific if it labels a single band of the expected size in the tissue of interest, or has a strong affinity for the antigen produced in a heterologous system. The identity of the antibody target protein is rarely confirmed by purification and sequencing, however in many cases this may be necessary. In this study we sought to characterize the myoplasm, a mitochondria-rich domain present in eggs and segregated into tadpole muscle cells of ascidians (urochordates). The targeted proteins of two antibodies that label the myoplasm were purified using both classic immunoaffinity methods and a novel protein purification scheme based on sequential ion exchange chromatography followed by two-dimensional gel electrophoresis. Surprisingly, mass spectrometry sequencing revealed that in both cases the proteins recognized are unrelated to the original antigens. NN18, a monoclonal antibody which was raised against porcine spinal cord and recognizes the NF-M neurofilament subunit in vertebrates, in fact labels mitochondrial ATP synthase in the ascidian embryo. PMF-C13, an antibody we raised to and purified against PmMRF, which is the MyoD homolog of the ascidian Phallusia mammillata, in fact recognizes mitochondrial HSP60. High resolution immunolabeling on whole embryos and isolated cortices demonstrates localization to the inner mitochondrial membrane for both ATP synthase and HSP60. We discuss the general implications of our results for antibody specificity and the verification methods which can be used to determine unequivocally an antibody's target.
Volume 8(1)
Pages e52996
Published 2013
DOI 10.1371/journal.pone.0052996
PII PONE-D-12-32899
PMID 23326373
PMC PMC3542361
MeSH Amino Acid Sequence Animals Antibodies / metabolism Antibodies, Monoclonal / metabolism Chaperonin 60 / genetics Chaperonin 60 / isolation & purification Chaperonin 60 / metabolism* Chromatography, Ion Exchange Electrophoresis, Gel, Two-Dimensional Embryo, Nonmammalian / cytology Embryo, Nonmammalian / embryology Embryo, Nonmammalian / metabolism Female Immunoblotting In Situ Hybridization Male Mitochondrial Membranes / metabolism Mitochondrial Proteins / genetics Mitochondrial Proteins / isolation & purification Mitochondrial Proteins / metabolism* Mitochondrial Proton-Translocating ATPases / genetics Mitochondrial Proton-Translocating ATPases / isolation & purification Mitochondrial Proton-Translocating ATPases / metabolism* Molecular Sequence Data Ovum / metabolism* Protein Binding Sequence Homology, Amino Acid Urochordata / embryology Urochordata / genetics Urochordata / metabolism*
IF 2.766
Times Cited 1
C.intestinalis / (O.japonicus) Wild C. int