Probing actin filament and binding protein interaction using an atomic force microscopy

• Published in: Journal of nanoscience and nanotechnology Vol. 14; no. 8; p. 5654
• Main Authors: Han, Sung-Woong, Morita, Kyohei, Simona, Patriche, Kihara, Takanori, Miyake, Jun, Banu, Mihaela, Adachi, Taiji
• Format: Journal Article
• Language: English
• Published: United States 01.08.2014
• Subjects: Actin Cytoskeleton - chemistry; Actin Cytoskeleton - metabolism; Microscopy, Atomic Force - methods; Molecular Probes; Protein Binding
• ISSN: 1533-4880
• DOI: 10.1166/jnn.2014.8777

Actin filaments play essential roles in many kinds of cellular functions by interacting with hundreds of actin binding proteins. Here we probe the interaction between actin filament and a binding protein, α-actinin, using an atomic force microscopy (AFM) and dynamic force spectroscopy (DFS). The distribution of rupturing events including specific and non-specific interactions of actin filament/α- actinin and BSA/α-actinin were analyzed. The rupture force of the actin filament/α-actinin binding was significantly larger than that of the BSA/α-actinin non-specific interaction, and the peaks represent typical multiple parallel bonds. In addition, based on the rupture forces in different loading rate DFS experiments, the dissociation constant of actin filament/α-actinin binding was estimated. The value is in good agreement with a previously reported value obtained by optical tweezer measurement. We expect that the present method will be useful for interaction measurement of actin filaments and many kinds of binding protein.