Microtubule-associated serine/threonine-protein kinase-like (MASTL) surfaceome proteomics analysis

Microtubule-associated serine/threonine-protein kinase-like (MASTL; a.k.a. Greatwall (Gwl) kinase) has an established role in the acceleration of cell cycle progression through inhibition of the PP2A-B55 phosphatase activity. Importantly, MASTL has emerged as a putative oncogene. Especially in breast cancer, high MASTL expression levels correlate with increased tumor growth and metastasis in vivo. We reported recently a kinase-independent role for MASTL as a regulator of cell adhesion, contractility and MRTF-A/SRF activity in breast cancer. This study also revealed that depletion of MASTL affects transcription and protein expression of multiple targets. Cell surface proteins are critical for characterization, isolation, and regulation of signaling. In order to reveal if MASTL affects breast cancer cells directly by regulation of surface proteins, we performed SILAC based surfaceome proteomics. Heavy and light isotope labelled endogenously produced surface proteins of MDA-MB-231 cells were purified by biotin enrichment and subjected to proteomics analysis.