Evidence for the association of synaptotagmin with glutathione S-transferases: implications for a novel function in human breast cancer.

Abstract Objective: To analyze the pattern of changes in GSTs in cancerous and adjacent non-cancerous tissues obtained from breast cancer patients undergoing surgery. Design and methods: Cytosolic GST purification, assay of GST, protein expression levels, and GST–synaptotagmin association were analyzed using standard biochemical techniques like GSH-affinity purification, spectrophotometry, SDS–PAGE, Western blots, and matrix-assisted laser desorption and ionization–time of flight (MALDI–TOF). Results: GST activity in cancerous tissues (0.26 U/mg protein) was significantly higher ( P Conclusions: Our results suggest a novel putative functional role for the GST–synaptotagmin complex in human breast cancers. As this association of GST M1–synaptotagmin was not seen in adjacent non-cancerous tissues, this can be used as a marker for breast cancers.