Fig. 1.

Schematic representation of the serum-free secretomics workflow. ① Protein secretion is probed by collecting cell culture supernatants under serum-free conditions for a defined treatment time range and is subsequently cleared to remove potential cell debris by centrifugation or by using a 0.45 μm syringe filter. ② Proteins are digested, and the resulting peptide samples are ③ analyzed by LC-MS/MS.