Static and dynamic lengths of neutrophil microvilli
Static and dynamic lengths of neutrophil microvilli
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DOI：
10.1073/pnas.95.12.6797
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发表时间：
1998-06-09
影响因子：
11.1
通讯作者：
Hochmuth, RM
中科院分区：
文献类型：
--
作者：
Shao, JY;Ting-Beall, HP;Hochmuth, RM
微绒毛的顶端含有大部分的l -选择素和p -选择素糖蛋白配体1 (PSGL-1)，可以促进中性粒细胞在内皮细胞上的初始阻滞。在停止后的滚动阶段，所涉及的分子键的寿命取决于血液流动的绝对压力所施加的拉力。通过两种不同的方法，电子显微镜和微移液管操作，我们获得了两个可比的中性粒细胞微绒毛长度，平均都接近0.3 μ m。我们还发现，在拉力作用下，微绒毛可以伸展（microvillus extension）或形成一个长而薄的膜筒（tether formation）。如果作用力小于或等于34 pN (+/- 3 pN)，微绒毛的长度会延长；如果力为bbb61pn (+/- 5pn)，微绒毛将以匀速形成系索，其速度与力呈线性关系。当作用力在34 ~ 61 pN（过渡区）之间时，单个微绒毛中膜与细胞骨架的关联程度将决定微绒毛是否延伸或系链形成。当微绒毛伸展时，它就像弹簧一样，弹簧常数约为43 pN/mu m。与刚性或不可伸展的微绒毛相比，微绒毛的伸展和系绳的形成都可以减少施加在粘接键上的拉力，从而延长粘接键在高生理纯应力下的持久性。
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 sheer stress of blood flow. With two different methods, electron microscopy and micropipette manipulation, we have obtained two comparable neutrophil microvillus lengths, both approximate to 0.3 mu m 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 less than or equal to 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 approximate to 43 pN/mu m. 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 sheer stresses.