Colorectal carcinoma-associated antigen Ca-Hb3 detected by one-dimensional SDS-polyacrylamide gel electrophoresis and liquid chromatography-tandem mass spectrometry.
OBJECTIVE
To comprehensively identify the proteins of tumor relative antigen Ca-Hb3 recognized by colorectal carcinoma monoclonal antibody Hb3.


METHODS
Ca-Hb3 was isolated by SDS-polyacrylamide gel electrophoresis (PAGE) followed by digestion with trypsin. Trypsin peptides were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The proteins identified by mass spectrometry were analyzed using bioinformatics.


RESULTS
Ca-Hb3 was identified as a CKAP4-like protein by Nano HPLC tandem mass spectrometry analysis. The molecular weight of CKAP4-like protein was 62.02 kDa, including one hydrophobic region, one transmembrane domain, five coiled coils, four glycosylation sites and forty-nine phosphorylation sites. CKAP4-like protein had a high homogeneity with DeltaNp63alpha. The characteristic expression of DeltaNp63alpha that is considered a potential oncogene in the isoforms of p63 was similar to that of Ca-Hb3.


CONCLUSIONS
Ca-Hb3 is probably a CKAP4-like protein, belonging to DeltaNp63alpha isoform of p63 family.
Sun
Shuo
S
Cancer Research Institute, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha 410078, Hunan Province, China.
Guo
Feng-Jie
FJ
Tong
Yong-Qing
YQ
Zhu
Jian-Gao
JG
Li
Guan-Cheng
GC
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology / Q000378:metabolism; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000276:immunology / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000276:immunology / Q000378:metabolism; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D020033:Protein Isoforms / Q000276:immunology / Q000378:metabolism; D053719:Tandem Mass Spectrometry
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D015295:Antigens, Tumor-Associated, Carbohydrate; D014408:Biomarkers, Tumor; C081876:CKAP4 protein, human; D008565:Membrane Proteins; D020033:Protein Isoforms; C530367:colorectal carcinoma-associated antigen, human