Static and dynamic lengths of neutrophil microvilli
AUTOR(ES)
Shao, Jin-Yu
FONTE
The National Academy of Sciences
RESUMO
Containing most of the L-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) on their tips, microvilli are believed to promote the initial arrest of neutrophils on endothelium. At the rolling stage following arrest, the lifetimes of the involved molecular bonds depend on the pulling force imposed by the shear stress of blood flow. With two different methods, electron microscopy and micropipette manipulation, we have obtained two comparable neutrophil microvillus lengths, both ≈0.3 μm in average. We have found also that, under a pulling force, a microvillus can be extended (microvillus extension) or a long thin membrane cylinder (a tether) can be formed from it (tether formation). If the force is ≤34 pN (± 3 pN), the length of the microvillus will be extended; if the force is >61 pN (± 5 pN), a tether will be formed from the microvillus at a constant velocity, which depends linearly on the force. When the force is between 34 pN and 61 pN (transition zone), the degree of association between membrane and cytoskeleton in individual microvilli will dictate whether microvillus extension or tether formation occurs. When a microvillus is extended, it acts like a spring with a spring constant of ≈43 pN/μm. In contrast to a rigid or nonextendible microvillus, both microvillus extension and tether formation can decrease the pulling force imposed on the adhesive bonds, and thus prolonging the persistence of the bonds at high physiological shear stresses.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=22640Documentos Relacionados
- Abdominal Ultrasound. Static and Dynamic Scanning
- Static and dynamic analysis of reinforced concrete shells
- Bacterial Adhesion under Static and Dynamic Conditions
- Activation of human muscles at short muscle lengths during maximal static efforts.
- X-ray dynamic observation of cervical degenerative disease induced by unbalanced dynamic and static forces in rats