Harms Brian D, Bassi Gina M, Horwitz Alan Rick, Lauffenburger Douglas A
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Biophys J. 2005 Feb;88(2):1479-88. doi: 10.1529/biophysj.104.047365.
Migrating cells can sustain a relatively constant direction of lamellipodial protrusion and locomotion over timescales ranging from minutes to hours. However, individual waves of lamellipodial extension occur over much shorter characteristic times. Little understanding exists regarding how cells might integrate biophysical processes across these disparate timescales to control the directional persistence of locomotion. We address this issue by examining the effects of epidermal growth factor (EGF) stimulation on long-timescale directional persistence and short-timescale lamellipodial dynamics of EGF receptor-transfected Chinese hamster ovary cells migrating on fibronectin-coated substrata. Addition of EGF increased persistence, with the magnitude of increase correlating with fibronectin coating concentration. Kymographic analysis of EGF-stimulated lamellipodial dynamics revealed that the temporal stability of lamellipodial protrusions similarly increased with fibronectin concentration. A soluble RGD peptide competitor reduced both the persistence of long-timescale cell paths and the stability of short-timescale membrane protrusions, indicating that cell-substratum adhesion concomitantly influences lamellipodial dynamics and directional persistence. These results reveal the importance of adhesion strength in regulating the directional motility of cells and suggest that the short-timescale kinetics of adhesion complex formation may play a key role in modulating directional persistence over much longer timescales.
迁移细胞能够在从数分钟到数小时的时间尺度上维持相对恒定的片状伪足突出方向和运动方向。然而，片状伪足延伸的单个波发生的特征时间要短得多。关于细胞如何整合跨越这些不同时间尺度的生物物理过程以控制运动方向的持续性，人们了解甚少。我们通过研究表皮生长因子（EGF）刺激对在纤连蛋白包被的基质上迁移的EGF受体转染的中国仓鼠卵巢细胞的长时间尺度方向持续性和短时间尺度片状伪足动力学的影响来解决这个问题。添加EGF增加了持续性，增加的幅度与纤连蛋白包被浓度相关。对EGF刺激的片状伪足动力学进行的波谱分析表明，片状伪足突出的时间稳定性同样随纤连蛋白浓度增加。一种可溶性RGD肽竞争者降低了长时间尺度细胞路径的持续性以及短时间尺度膜突出的稳定性，表明细胞与基质的粘附同时影响片状伪足动力学和方向持续性。这些结果揭示了粘附强度在调节细胞定向运动中的重要性，并表明粘附复合物形成的短时间尺度动力学可能在更长时间尺度上调节方向持续性方面起关键作用。
