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A03 NISHIZAKA, Takayuki |Proposed Research Projects (2016-2017)

Paper | Original Paper

2017

Daisuke Nakane and Takayuki Nishizaka*,
Asymmetric distribution of type IV pili triggered by directional light in unicellular cyanobacteria,
Proceedings of the National Academy of Sciences 114, 6593-6598 (2017).

[Summary] The type IV pili (T4P) system is a supermolecular machine observed in prokaryotes. Cells repeat the cycle of T4P extension, surface attachment, and retraction to drive twitching motility. Although the properties of T4P as a motor have been scrutinized with biophysics techniques, the mechanism of regulation remains unclear. Here we provided the framework of the T4P dynamics at the single-cell level in Synechocystis sp. PCC6803, which can recognize light direction. We demonstrated that the dynamics was detected by fluorescent beads under an optical microscope and controlled by blue light that induces negative phototaxis; extension and retraction of T4P was activated at the forward side of lateral illumination to move away from the light source. Additionally, we directly visualized each pilus by fluorescent labeling, allowing us to quantify their asymmetric distribution. Finally, quantitative analyses of cell tracking indicated that T4P was generated uniformly within 0.2 min after blue-light exposure, and within the next 1 min the activation became asymmetric along the light axis to achieve directional cell motility; this process was mediated by the photo-sensing protein, PixD. This sequential process provides clues toward a general regulation mechanism of T4P system, which might be essentially common between archaella and other secretion apparatuses.

2016

Yoshiaki Kinosita, *Nariya Uchida, Daisuke Nakane, and *Takayuki Nishizaka,
Direct observation of rotation and steps of the archaellum in the swimming halophilic archaeon Halobacterium salinarum,
Nature Microbiology 1, 16148/1-9 (2016).

Akihiro Tanaka, Daisuke Nakane, Masaki Mizutani, Takayuki Nishizaka, *Makoto Miyata,
Directed binding of gliding bacterium, Mycoplasma mobile, shown by detachment force and bond lifetime,
mBio 7, e00455-16 (2016).

*Mitsuhiro Sugawa, Kei-ichi Okazaki, Masaru Kobayashi, Takashi Matsui, Gerhard Hummer, Tomoko Masaike, and *Takayuki Nishizaka,
F1-ATPase conformational cycle from simultaneous single-molecule FRET and rotation measurements,
Proceedings of the National Academy of Sciences of the United States of America 113, E2916-2924 (2016).