Mass spectrometry based analysis of erythrocyte membrane associated proteins in chronic myeloid leukemia patients in Sri Lanka

The research reported in this paper was conducted to analyze erythrocyte membrane associated proteins (ERMBPs) of some of chronic myeloid leukemia (CML) patients and selected individuals of Sri Lanka employing one dimensional sodium dodecyl sulphate poly acrylamide gel electrophoresis (1D-SDS-PAGE) combined with matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI–TOF-MS). Erythrocyte membranes from blood were isolated by osmotic lysis, centrifugation and washings. ERMBPs were separated on 1D-SDS-PAGE, visualized by silver staining and the separated protein bands dissected out from the gel and were subjected to digestion by proteolytic enzyme, trypsin, and the resulting peptide mixture was analyzed by MALDI-TOF-MS. Resulting experimental peptide mass values were analyzed by peptide mass fingerprint (PMF) technique. From this analysis 10 ERMBPs including α and β spectrin, ankyrin, band 3, band 4.1, band 4.2, band 7, dematin, actin, 55 KDa erythrocyte membrane protein were identified accurately with their primary structure information. The study was able to provide some evidence for Cathepsin associated cleavage of Band 3 anion transport protein in CML patients reported previously. In addition we were able to detect changes in gel bands between healthy controls and CML patients around the area of 20 kDa in the 1 D-SDS-PAGE. It was identified as nuclear protein Dbf 4 related factor 1 isoform 2. Although erythrocytes are devoid of nuclei, such unexpected nuclear proteins have been identified in previous research. We were successful in identifying several human ERMBPs with available resources. As the identified proteins were known to be related to pathology of some of the hematological diseases, this methodology could be extended to detect the protein changes in erythrocyte membrane protein associated diseases. Therefore, this initial research would at some point lead to discovery of biomarkers to these hematological diseases in Sri Lanka.