Localization of Actin-Interacting Proteins to the Phagosome of Human Neutrophils and RAW 264.7 Macrophages

摘要

Mass spectrometry may be used to identify proteins that function in cellular signaling systems that depend on the cytoskeleton. We localized two types of actin-binding proteins Annexin and Haematopoietic specific protein 1 (HS1), to the sub-cellular organelle the phagosome by LC-MS/MS and that was confirmed by immuno staining or transient expression of GFP fusions in live cells. HS1, a protein known to bind to actin, is exclusively expressed in cells and tissues of haematopoietic and lymphoid origins and may be involved in immune responses. It is a major substrate of protein-tyrosine kinase(s) regulated by B-cell antigen receptors and is associates with the SH2 domain of Lyn kinase upon receptor-mediated signaling. Annexin, a protein that is associated in various intra- and extracellular processes including inflammatory signaling, binds actin and plays a functional role in innate immunity.