Date on Master's Thesis/Doctoral Dissertation
Biochemistry and Molecular Biology
McLeish, Kenneth R.
Neutrophil; Exocytosis; Proteomic
Exocytosis of intracellular granules is critical for conversion of inactive, circulating neutrophils to fully activated cells. The p38 MAPK pathway plays a central role in neutrophil exocytosis, although its mechanism of action is unknown. We used several proteomic approaches to identify granule proteins and find targets of the p38 MAPK and its downstream kinase, MK2, on granules. Our analysis identified 286 proteins on neutrophil granules, four of which were known MK2 substrates. Known p38 substrates were not detected. However, MRP-14 was identified as a novel p38 MAPK substrate. MRP-14 was phosphorylated by p38 MAPK in neutrophils upon cell stimulation and translocated to plasma membranes and gelatinase granules, as well as to Triton X-100-insoluble structures at the base of lamellipodia. Phosphorylation of the MRP-14 by p38 MAPK increased binding to actin in vitro. These results suggest that MRP-14 is a potential mediator of p38 MAPK-dependent exocytosis in human neutrophils.
Lominadze, George 1978-, "Defining the mechanisms of neutrophil exocytosis using proteomic techniques." (2005). Electronic Theses and Dissertations. Paper 852.