Table 3. Quantitation of Cos2-GFP puncta motility along microtubules.

S2 cells expressing cos2-GFP and mCherry-tubulin were treated with 5 µM cytochalasin for 18 hours. Cytochalasin disrupts the actin cytoskeleton, allowing formation of long MT projections, along which Cos2-GFP puncta appear to co-localize and move. MT projections are defined as a projection measuring more than 5µm in length and has a MT track that is labeled by mCherry-tubulin. Motile puncta were defined by previously described criteria outlined in the Methods section. Eighty-one percent of all puncta visible on MT projections moved in a manner consistent with them tracking along MTs.

Cell Image	Microtubule projections per cell	Motile puncta per microtubule projections	Total puncta observed	Total puncta on microtubules exhibiting motility (%)
1	10	11	21	52.4
2	12	3	3	100
3	7	27	29	93.1
4	2	5	5	100
5	5	18	21	85.7
Totals:	36	64	79	81