Macrophage integrin aDb2 promotes macrophage retention and accumulation within inflamed tissue, a key event in development of chronic inflammation. Recently, the P5 peptide was identified as a specific inhibitor for integrin aDb2 interaction with 2-(ω-carboxyethyl) pyrole (CEP), a ligand at inflammatory sites. This thesis aims to identify integrin aD I-domain amino acids involved in binding P5 peptide and likewise to CEP. We propose that non-conserved, basic amino acids of the integrin aDb2 I-domain are responsible for binding to P5 peptide and likewise to CEP. Eight amino acids were analyzed by generating six mutant aD I-domains: K180[A], R189[Q], K205[L], HHK223-225[NIT], K233[A], and K246[A]. Mutagenic constructs were created using PCR site-directed mutagenesis, then transformed into E.coli BL21 cells for IPTG-induced protein expression. Of the 6 mutant I-domains analyzed, amino acid K246 was critical in binding to P5 peptide and CEP through ForteBio Protein-Protein Assay, as well as to CEP by cell adhesion assay.

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Single-particle tracking (SPT) is a method used to study the diffusion of various molecules within the cell. SPT involves tagging proteins with optical labels and observing their individual two-dimensional trajectories with a microscope. The analysis of this data provides important information about protein movement and mechanism, and is used to create multistate biological models. One of the challenges in SPT analysis is the variety of complex environments that contribute to heterogeneity within movement paths. In this thesis, we explore the limitations of current methods used to analyze molecular movement, and adapt analytical methods used in animal movement analysis, such as correlated random walks and first-passage time variance, to SPT data of leukocyte function-associated antigen-1 (LFA-1) integral membrane proteins. We discuss the consequences of these methods in understanding different types of heterogeneity in protein movement behaviour, and provide support to results from current experimental work. / Applied Mathematics