National Institute of Advanced Industrial Science and Technology (AIST) and Kanazawa University Kien Xuan Ngo, Noriyuki Kodera Taro Q.P. Uyeda
Cofilin has an actin filament severing activity. Contrary to previous predictions based on indirect evidence, we found by high speed AFM real time imaging that severing rarely occurs when cofilin is sparsely bound along actin filaments. In this video, four independent image sequences are merged. Conditions: F buffer containing 1 mM ATP and 0, 10 or 40 nM cofilin. In this video, three data sets which represent three cases of the absence or presence of cofilin are sequentially shown and indicated before each sequence begins as (i) Control: Without Cofilin, (ii) 10 nM Cofilin (two different image sequences), and (iii) 40 nM Cofilin. Note that severing of actin filaments was not observed not only in the absence but also in the presence of 10 nM cofilin. In the presence of 40 nM cofilin, severing was infrequently observed (red arrowheads) only near clusters (white arrowheads). Images were taken at 0.5 frames/s, except in the presence of 40 nM cofilin they were recorded at 0.25 frames/s, and the video is played at 5 frames/s. The width of the imaged field: 830 nm, Z-scale: 0–12 nm.
(2015.06.18)