Klp6₄₄₀His enhances tubulin nucleation.

<p>(<b>A</b>) Polymerisation of 1.5 µM <i>S. pombe</i> GMPCPP tubulin visualised by dark field microscopy before and 37 min after adding either buffer or Klp6₄₄₀His. Compared to buffer alone (left) addition of Klp6₄₄₀His drives formation of many short microtubules, indicating a nucleation rather than elongation effect. The effect of Klp6₄₄₀His on the assembly of (<b>B</b>) 1.5 µM <i>S. pombe</i> or (<b>C</b>) 1.5 µM pig brain GMPCPP tubulin into microtubules at subcritical concentration was monitored by light scattering at 350 nm. Increasing Klp6₄₄₀His accelerates the rate of increase in light scattering. Dark field microscopy suggests the increase results from higher microtubule numbers due to increased microtubule nucleation (scale bar: 10 µm).