IDENTIFICATION OF SURFACE PROTEOME OF B CELL ACUTE LYMPHOBLASTIC LEUKEMIA CELL LINE

Abstract

B-cell acute lymphoblastic leukemia is characterized by over and uncontrolled expression of B lymphocytes. B-ALL may occur as a result of aberrant cytosolic signal transduction and molecular abnormalities such as gene mutations, abnormal protein interactions, and an un-arrested cell cycle. Due to these abnormalities, surface proteins that compromised one-third of the proteome show different expressions compared to the healthy cells. These differences are currently in use for diagnostic and treatment approaches. Here, we aimed to isolate and identify the surface proteins of the CCRF-SB cell line to identify new, additional possible target antigens with the mass spectrometrybased proteomics approach using two different surface protein isolation strategies. The surface proteins of CCRF-SB cells were isolated with the surface biotinylation method and N-linked glycoprotein enrichment methods. With the biotinylation method, we isolated 782 proteins with 1% FDR. Gene Ontology Cellular Compartment analysis showed that 467 of these isolated proteins are annotated as ‘Membrane’. 263 of those proteins are annotated as ‘Extracellular Space’. These isolated cell surface proteins include HLA protein complexes and well-known CD19 surface markers. With the Nlinked glycosylation enrichment method 229 protein identified with 1% FDR rate. Gene Ontology Cellular Compartment analysis showed that 155 of these isolated proteins are annotated as ‘Membrane’, 132 of those proteins are annotated as ‘Extracellular Space’. Both methods identified different proteins from each other. This result showed that to map the surfaceome of CCRF-SB cell line, it is required to combine these two enrichment methods.