Office Address

287 Physics Bldg.

Position Title

Assistant Professor fo Biophysics and Biomedical Physics

Areas of Interest

single molecular biophysics and biomedical physics; total internal fluorscent microscopy

Narrative Bio

We are investigating the chemical and mechanical properties of molecular motor, myosin, in the regulation of muscle contraction (myoin II) and transportation (myosin V) of cargos. Myosins utilize ATP hydrolysis energy to perform mechanical work with actin filaments and are responsible for diverse physiological processes including cell division, muscle contraction, maintaining morphology, and migration. Currently myosin superfamily has been categorized into 26 classes. Human has 39 genes encoding myosin. I recently focus on class V myosin, which is a transporter for many cargos, such as melanosome in melanocytes, mRNA in yeasts, and ER in neurons. A single molecule fluorescently-labeled myosin V was visualized by total internal reflection fluorescent microscopy and was found that myosin V takes 36 nm step. Interestingly such a small molecular motor steps along actin filament tracks, like human walk.

To understand the mechanical properties of acto-myosin system, we have used single molecule techniques and solution transient kinetics techniques. Using total internal reflection fluorescent (TIRF) microscopy, we can visualize single molecule of myosin and a nucleotide (ATP) as a spot and measure the detail of myosin stepping mechanisms and ATP binding and dissociation events, simultaneously. Our results directly evidenced that a single myosin V molecule takes tight coupling mechanisms (i.e. one ATP hydrolysis takes one step of myosin molecule). Another technique is solution transient kinetics to measure the detail characteristics of ATP hydrolysis cycle mechanism of the myosin.

Publications

 A list of Dr. Sakamoto's publications can be found at PubMed-Sakamoto

Education

• B.S. Physics, Nihon University, Japan
• M.S. Physics/Biophysics, Kanazawa University, Japan
• Ph.D. Physics/Biophysics, Kanazawa University, Japan

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