Pathway: Activation of RAS in B cells
Reactions in pathway: Activation of RAS in B cells :
Activation of RAS in B cells
RasGRP1 and RasGRP3 bind diacylglycerol at the plasma membrane (Lorenzo et al. 2001) and are phosphorylated by protein kinase C (Teixeira et al. 2003, Zheng et al. 2005). Phosphorylated RasGRP1 (Roose et al. 2007) and RasGRP3 (Ohba et al. 2000, Yamashita et al. 2000, Rebhun et al. 2000, Lorenzo et al. 2001) then catalyze the exchange of GDP for GTP bound by RAS, thereby activating RAS.
Adaptive immunity refers to antigen-specific immune response efficiently involved in clearing the pathogens. The adaptive immune system is comprised of B and T lymphocytes that express receptors with remarkable diversity tailored to recognize aspects of particular pathogens or antigens. During infection, dendritic cells (DC) which act as sentinels in the peripheral tissues recognize and pick up the pathogen in the form of antigenic determinants and then process these antigens and present them to T cells. These T cells of appropriate specificity respond to the antigen, and either kill the pathogen directly or secrete cytokines that will stimulate B lymphocyte response. B cells provide humoral immunity by secreting antibodies specific for the pathogen or antigen.
Humans are exposed to millions of potential pathogens daily, through contact, ingestion, and inhalation. Our ability to avoid infection depends on the adaptive immune system and during the first critical hours and days of exposure to a new pathogen, our innate immune system.