Pathway: Role of phospholipids in phagocytosis
Reactions in pathway: Role of phospholipids in phagocytosis :
Role of phospholipids in phagocytosis
Phospholipases play an integral role in phagocytosis by generating essential second messengers. An early step in phagocytic signaling is the association of PIP2 and IP3 with the phagocytic cup. These are formed by the activity of phosphoinositol kinases and phospholipases. PI3K is has been shown to accumulate at phagocytic cups and converts PI (4,5)P2 to PI (3,4,5)P3. These phosphoinositides are capable of binding and increasing the activity of proteins that regulate the actin cytoskeleton. Phospholipases are lipid modifying enzymes that produce lipid mediators such as diacylglycerol (DAG), arachidonic acid (AA) and IP3. Phopsholipases PLA, PLC and PLD have been shown to be involved in antibody (IgG) mediated phagocytosis. The PLC product IP3 stimulates release of calcium from the endoplasmic reticulum. This Ca+2 concentration increase is greatest in the cytoplasm surrounding the phagocytic cup. Calcium is involved in the various stages of phagosome formation, including phagocytic ingestion and phagosome maturation.
Innate immunity encompases the nonspecific part of immunity tha are part of an individual's natural biologic makeup
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.