What is the molecular mechanis
What is the molecular mechanism, discussed in class and drawn onthe board, used by white blood cells to move (e.g., as they chasebacteria)?
Tubulin polymerization and depolymerization
Actin polymerization and depolymerization
Intermediate filament polymerization and depolymerization
Flagella
Answer:
Actin polymerisation and depolymerisation
Once the leukocytes comes out of the circulation, they migratethrough the tissue towards the site of injury. This is calledchemotaxis. This occurs because of a chemical gradient. The chemoattractants that helps this process are mainly the bacterialproducts – the peptides with N formyl methionine terminal aminoacids. There are endogenous chemo attractants also, which includescytokines, leukotrienes, complement components etc. Thesechemotactic agents binds to transmembrane G protein coupledreceptors on the surface of leukocytes. The signals generated fromthese receptors activates second messengers that increase thecytoplasmic calcium as well as guanosine phosphatases of Rac, Rhoand cdc42 family. These results in actin polymerisation andincrease in actin at the leading end of the cell and localisationof myosin filament at the back. Then the leukocytes move byextending filo podiatrist.