SRC Family Negative Regulatory Phosphorylation Site belongs to the protein kinase superfamily, Tyr protein kinase family, SRC subfamily. It contains one protein kinase domain, one SH2 domain and one SH3 domain. It may serve as part of a signaling pathway coupling the Fc receptor to the activation of the respiratory burst and may also contribute to neutrophil migration and may regulate the degranulation process of neutrophils. SRC Family Negative Regulatory Phosphorylation Site is expressed predominantly in cells of the myeloid and B lymphoid lineages. There are two named isoforms.