Aim: To evaluate the receptor protein which can specifically bind to beta(2)GP I on the membrane of hepatocellular carcinoma (HCC) cell line SMMC-7721, and to study the biological function of the receptor.
Methods: Through beta(2)GP I -affinity chromatography column, the peptid-polysome-mRNA complex, which can specially bind to beta(2)GP I, stayed with the column and was separated from the whole polysome of liver cells, and then eluted and collected. Using cDNA synthesis kit and cDNA PCR kit, the corresponding cDNA was obtained and sequenced. RT-PCR was used to amplify annexin II, and flow cytometry was used to study the competitive binding of annexin II with beta(2)GP I to SMMC-7721.
Results: A total of 1.1 kb of the cDNA fragment of the specific binding protein of beta(2)GP I on liver cell membrane was obtained. The sequence of cDNA shared high homology with human annexin II (98%). Annexin II was expressed on the membrane of SMMC-7721, and could compete with beta(2)GP I for combining with SMMC-7721.
Conclusion: The receptor for beta(2)GP I on membrane of SMMC-7721 cells is annexin II, which might bridge HBV to infect hepatocytes.