Proteomics of a toxic dinoflagellate Alexandrium catenella DH01: Detection and identification of cell surface proteins using fluorescent labeling

Alexandrium catenella DH01 is a toxic dinoflagellate species that is able to not only produce paralytic shellfish toxins, but also cause harmful algal blooms along the coast of China. In this study, we presented a new protocol for specific labeling and detection of the cell surface proteins (CSPs) of A. catenella DH01 cells using CyDye difference gel electrophoresis (DIGE) fluor minimal dyes. CSPs were identified using two-dimensional gel electrophoresis (2-DE) and MALDI TOF-TOF mass spectrometry (MS). The results showed that the fluorescent cyanine dye Cy3 could specifically label the CSPs of A. catenella DH01, with minimal labeling of intracellular proteins. Among three protein extraction methods evaluated, the Trizol method was the most efficient to extract CSPs with respect to protein spot number and resolution. Forty-one CSPs were separated and identified from A. catenella DH01 by 2-DE, in which 14 were identified in the protein database using MALDI TOF-TOF MS analysis. This work represents the first attempt to investigate the CSPs of A. catenella using the CyDye DIGE fluor dyeing method that provides a potentially important tool for future comprehensive characterization of CSPs and elucidation of the physiological functions of CSPs in dinoflagellates.