Fig. 1.

Categorization of proteins identified in USSC secretome by LC-MS/MS. A, Based on UniProt annotation, 993 proteins were found to be localized extracellularly. The USSC secretome further included 884 membrane associated proteins that might be found in the secretome because of shedding and 118 cell surface proteins (multiple protein entries possible). In total, 1520 proteins were determined. B, SignalP and SecretomeP algorithms revealed that 385 proteins are classically secreted and 276 proteins are nonclassically secreted. GO slim term extracellular included 487 proteins that were not predicted as secreted by SignalP and SecretomeP. Additionally, eight proteins were predicted to be localized at the cell surface. Overall, we identified 1156 proteins predicted to be secreted and 364 contaminants. C, These 1156 were assigned biological processes that in part play important roles during nerve regeneration (multiple protein entries possible) such as cell differentiation, development, cell communication and cell division.