FIGURE 2.

GSNL-1 severs actin filaments. A, Alexa488-labeled actin filaments were tethered to a glass coverslip and treated with buffer alone (a, b, k, and l) or varying concentrations of GSNL-1 in the same buffer (c–j and m–t) for 3 min. The buffer in a–j contained 0.1 mm CaCl₂, and the buffer in k–t contained 5 mm EGTA. The filaments were observed before (a, c, e, g, i, k, m, o, q, and s) and 3 min after the incubation (b, d, f, h, j, l, n, p, r, and t), and micrographs of the same fields were taken. Bar, 10 μm. B, Alexa488-labeled actin filaments were preincubated with buffer containing 10 mm potassium phosphate (a and c) or no phosphate (e and g). Then buffer alone containing 10 μm CaCl₂ and no phosphate (b and f) or the same buffer containing 40 nm GSNL-1(d and h) was infused and incubated for 2 min. The filaments were observed before (a, c, e, and g) and after the incubation (b, d, f, and h), and micrographs of the same fields were taken. Bar, 10 μm.