Studies of integrins' lateral dynamics at a single particle level

Abstract

<p>One of the important factors in controlling the dynamics, structure, and functioning of the cell membrane is the lateral diffusion of membrane proteins and lipids. Integrins are one of the ubiquitous transmembrane proteins that are vital for numerous cellular functions. Integrins' lateral mobility and rearrangement is essential for integrins primary function of cell-extracellular matrix adhesion, cell-cell adhesion, and signaling. Lateral movement allows integrins to associate with extracellular ligand and other cytoplasmic and membrane proteins to incite biological activity such as signaling and downstream effects. This thesis describes the role of both downstream and upstream effectors, such as extracellular ligand, selected cytoplasmic and membrane proteins in altering integrins' lateral dynamics in the cell membrane. Integrins' lateral mobility is studied using two popular fluorescence techniques: single particle tracking (SPT) with ligand-functionalized quantum dots (QDs) and fluorescence recovery after photobleaching (FRAP) with integrin-Venus fusion proteins. The molecular biology technique called RNA interference (RNAi) is used to selectively reduce the expression of a protein of interest in the cell. The results prove that the ligand binding affinity, selected cytoplasmic and membrane proteins do affect lateral mobility of a subset of integrins.</p>