In: Biology
What is the molecular mechanism, discussed in class and drawn on the board, used by white blood cells to move (e.g., as they chase bacteria)?
Tubulin polymerization and depolymerization
Actin polymerization and depolymerization
Intermediate filament polymerization and depolymerization
Flagella
Actin polymerisation and depolymerisation
Once the leukocytes comes out of the circulation, they migrate through the tissue towards the site of injury. This is called chemotaxis. This occurs because of a chemical gradient. The chemo attractants that helps this process are mainly the bacterial products - the peptides with N formyl methionine terminal amino acids. There are endogenous chemo attractants also, which includes cytokines, leukotrienes, complement components etc. These chemotactic agents binds to transmembrane G protein coupled receptors on the surface of leukocytes. The signals generated from these receptors activates second messengers that increase the cytoplasmic calcium as well as guanosine phosphatases of Rac, Rho and cdc42 family. These results in actin polymerisation and increase in actin at the leading end of the cell and localisation of myosin filament at the back. Then the leukocytes move by extending filo podiatrist.