Shotgun analysis of the marine mussel Mytilus edulis hemolymph proteome and mapping the innate immunity elements.

The marine mussel innate immunity provides protection to pathogen invasion and inflammation. In this regard, the mussel hemolymph takes a main role in the animal innate response. Despite the importance of this body fluid in determining the physiological condition of the animal, little is known about the molecular mechanisms underlying the cellular and humoral responses. In this work, we have applied a MS (nano-LC-MS/MS) strategy integrating genomic and transcriptomic data with the aim to: (i) identify the main protein functional groups that characterize hemolymph and (ii) to map the elements of innate immunity in the marine mussel Mytilus edulis hemolymph proteome. After sample analysis and first protein identification based on MS/MS data comparison, proteins with unknown functions were annotated with blast using public database (nrNCBI) information. Overall 595 hemolymph proteins were identified with high confidence and annotated. These proteins encompass primary cellular metabolic processes: energy production and metabolism of biomolecules, as well as processes related to oxidative stress defence, xenobiotic detoxification, drug metabolism, and immune response. A group of proteins was identified with putative immune effector, receptor, and signaling functions in M. edulis. Data are available via ProteomeXchange with identifier PXD001951 (http://proteomecentral.proteomexchange.org/dataset/PXD001951).