Carmichael’s Concise Review
Coming Events 2017
New Zealand Conference on Microscopy January 31–February 3, 2017
Auckland, New Zealand
www.microscopy2017.co.nz
AMAS XIV - 14th Australian Microbeam
Biennial Symposium February 6–10, 2017 Brisbane, Australia
http://microscopy.org.au/amas/
Biophysical Society 61st Annual Meeting February 11–15, 2017 New Orleans, LA
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Pittcon 2017 Conference & Expo March 5–9, 2017 Chicago, IL
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Novel Techniques in Microscopy April 2–5, 2017 San Diego, CA
www.osa.org/en-us/meetings/global_calendar/events/ novel_techniques_in_microscopy_%281%29
253rd ACS National Meeting & Exposition April 2–6, 2017 San Francisco, CA
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Microscopy & Microanalysis 2017 August 6–10, 2017
St. Louis, MO
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2018
Microscopy & Microanalysis 2018 August 5–9, 2018
Baltimore, MD
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2019
Microscopy & Microanalysis 2019 August 4–8, 2019
Portland, OR
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2020
Microscopy & Microanalysis 2020 August 2–6, 2020
Milwaukee, WI
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2021
Microscopy & Microanalysis 2021 August 1–5, 2021
Pittsburgh, PA
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More Meetings and Courses Check the complete calendar near the back of this magazine.
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Figure 1 : Anterograde and retrograde IFT trains use different microtubules in the same doublet. (A) Kymograph showing directional IFT train movement during live-cell imaging of Chlamydomonas (IFT27-GFP strain). In this kymograph a green particle moving in the anterograde direction tracks a line from the upper left to the lower right; similarly for a magenta particle traveling retrograde from upper right to lower left. Vertical drop indicates distance traveled, and slope indicates rate of movement. (B) Virtual tomogram slice, showing cross-sectional view of anterograde trains (green arrowheads) and retrograde trains (magenta arrowheads) stopped next to each other on the same doublet. Scale bar = 50 nm. (C) Segmentation of an axoneme showing anterograde trains (green) and retrograde trains (magenta) moving simultaneously on microtubule doublet 9. Scale bar = 25 nm.
doi: 10.1017/S1551929516001097 2017 January
Two-Way Traffi c Determined by Different Tracks in Cilia
Stephen W. Carmichael and Jeffery L. Salisbury Mayo Clinic , Rochester , MN 55905
carmichael.stephen@
mayo.edu ,
salisbury.jeff
ery@mayo.edu
T e cilium and the fl agellum are conserved organelles that play fundamental roles in cellular signaling, sensing, and motility. Cilia and flagella have a complex microtubule-based axoneme that includes nine peripheral microtubule doublets, each comprised of a complete A-tubule and an incomplete B-tubule. However, the function of this distinctive geometry has remained unknown until now. In a recent study, Ludek Stepanek and Gaia Pigino use the model organism Chlamydomonas to reveal a new understanding of the functional signifi- cance of the A- and B-tubule structure [ 1 ].
It is known that ciliary microtubule doublets function as “railways” for intrafl agellar transport (IFT), the process required for the assembly and disassembly of cilia. Large protein complexes, known as IFT trains, rapidly traverse up and down the cilium to move ciliary “building blocks” between the cell body and the distal tip of the cilium where the assembly of the cilium occurs. Electron microscopy (EM) has shown that the IFT trains move along the doublets. However, it has not been clear how the railway is organized to avoid collisions between anterograde and retrograde trains. Stepanek and Pigino used total internal fl uorescence (TIRF) microscopy to show that trains tagged with green fl uorescent protein interacted with each other in both the anterograde and retrograde directions. However, trains headed in the opposite direction did not interact, suggesting
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