Proteomic analysis of the cell-surface membrane in chronic lymphocytic leukemia: identification of two novel proteins, BCNP1 and MIG2B.
B-cell-specific plasma-membrane proteins are potential targets for either small molecule or antibody-based therapies. We have sought to annotate proteins expressed at the cell surface membrane in patients with chronic lymphocytic leukemia (CLL) using plasma-membrane-based proteomic analysis to identify previously uncharacterized and potentially B-cell-specific proteins. Proteins from plasma-membrane fractions were separated on one-dimensional gels and trypsinized fractions subjected to high-throughput MALDI-TOF mass spectrometry. Using this method, many known B-cell surface antigens were detected, but also known proteins not previously described in this disease or in this cellular compartment, including cell surface receptors, membrane-associated enzymes and secreted proteins, and completely unknown proteins. To validate the method, we show that BLK, a B-cell-specific kinase, is located in the CLL-plasma-membrane fraction. We also describe two novel proteins (MIG2B and B-cell novel protein #1, BCNP1), which are expressed preferentially in B cells. MIG2B is in a highly conserved and defined gene family containing two plasma-membrane-binding ezrin/radixin/moesin domains and a pleckstrin homology domain; the Caenorhabditis elegans homolog (UNC-112) is a membrane-associated protein that colocalizes with integrin at cell-matrix adhesion complexes. BCNP1 is a completely unknown protein with three predicted transmembrane domains, with three alternatively spliced final exons. Proteomic analysis may thus define new potential therapeutic targets.
Boyd
R S
RS
Oxford Glycosciences (UK) Ltd, Abingdon, Oxford, UK.
Adam
P J
PJ
Patel
S
S
Loader
J A
JA
Berry
J
J
Redpath
N T
NT
Poyser
H R
HR
Fletcher
G C
GC
Burgess
N A
NA
Stamps
A C
AC
Hudson
L
L
Smith
P
P
Griffiths
M
M
Willis
T G
TG
Karran
E L
EL
Oscier
D G
DG
Catovsky
D
D
Terrett
J A
JA
Dyer
M J S
MJ
D051017:Apoptosis Regulatory Proteins; D001402:B-Lymphocytes / Q000737:chemistry* / Q000473:pathology; D001483:Base Sequence; D015153:Blotting, Western; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000473:pathology*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D016366:Open Reading Frames; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D051017:Apoptosis Regulatory Proteins; C477322:FERMT3 protein, human; D008565:Membrane Proteins; C477321:NIBAN3 protein, human; D009363:Neoplasm Proteins; D020033:Protein Isoforms