**10. References**


	- [16] Ohno-Jinno A, Isogai Z, Yoneda M, Kasai K, Miyaishi O, Inoue Y, Kataoka T, Zhao JS, Li H, Takeyama M, Keene DR, Sakai LY, Kimata K, Iwaki M, Zako M (2008) Versican and Fibrillin-1 Form a Major Hyaluronan-Binding Complex in the Ciliary Body. Invest Ophthalmol Vis Sci. 49: 2870-2877.

**Chapter 8** 

© 2012 Xi et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

© 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

distribution, and reproduction in any medium, provided the original work is properly cited.

and reproduction in any medium, provided the original work is properly cited.

**Dynamic Mechanical Response of** 

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/49977

**1. Introduction** 

**Epithelial Cells to Epidermal Growth Factor** 

Jun Xi, Lynn S. Penn, Ning Xi, Jennifer Y. Chen and Ruiguo Yang

**1.1. Mechanical properties of cells and their biological significances.** 

characterized by Young's modulus (Satcher Jr & Dewey Jr, 1996).

As a viscoelastic body, the cell exhibits both elastic and viscous characteristics (Kasza, 07). Although these mechanical properties have not been attributed wholly to a single element, such as the cytoskeletal network, the cytoplasm, the cell membrane, or the extracellular network (Janmey et al., 2007), it is agreed that they are determined predominantly by the cytoskeleton, a network of biopolymers in the form of actin filaments, microtubules, and intermediate filaments. The dynamic assembly and disassembly of these biopolymers give the cell the ability to move and to modulate its shape, elasticity, and mechanical strength in responses to mechanical and chemical stimuli from the external environment (Fletcher & Mullins, 2010). Among these cytoskeletal polymers, actin filaments are known to be primarily responsible for the rigidity of the cell. An increase in the concentration of actin filaments typically results in an increase in the rigidity of the cell, which can be

The cytoskeleton is also essential in regulation of cell signaling and trafficking (Janmey, 1998; Papakonstanti & Stournaras, 2008). In particular, the structure of the cytoskeleton plays an essential role in EGFR signaling and trafficking that is initiated by the binding of epidermal growth factor (EGF) to the EGF receptor (EGFR) (Ridley, 1994; Song et al., 2008). EGF is a protein molecule known to play a crucial role in the regulation of cell growth, proliferation, differentiation and motility. EGFR is a transmembrane receptor that consists of an extracellular ligand-binding domain, a transmembrane domain, an intracellular tyrosine kinase domain, and a C-terminal regulatory domain (Scaltriti & Baselga, 2006). Binding of EGF to the extracellular domain of EGFR leads to the dimerization of EGFR, which in turn stimulates tyrosine kinase activity of the receptors and triggers autophosphorylation of

