Tubulin isoforms identified in the brain by MALDI in-source decay.

Identification of biomarkers is a major issue for enhancement of chemotherapies. The molecular characterization of tissues necessitates the identification of thousands of biomolecules each participating in physiopathological processes. MALDI in-source decay (ISD) fragmentation has already been proven to be effective for protein characterization. However, the difficulty to identify proteins from complex mixtures such as tissue sections can limit the applications of this technique. In this study, we evidenced that tubulin has an unusual fragmentation pathway in the MALDI source. This striking property allowed the detecting of several mouse brain tubulin isotypes simultaneously by simply using laser fragmentation. Tubulin isoforms are consistent markers of a bad prognosis of solid tumors and could be the target of targeted chemotherapies. Such a direct molecular printout of tubulin in tissues is a milestone that should be useful either at preclinical or clinical stage.