Fig. 5. Phosphorylation of 3F3/2 epitopes in S2 lysed cells. In all images DNA is shown in blue and 3F3/2 antibody staining in red. (A) S2 cell lysed in the absence of the phosphatase inhibitor microcystin (T-Mc). 3F3/2 epitopes are only detectable at the spindle poles (arrowhead). (B,C) S2 cells lysed in the presence of microcystin (T+Mc). Prometaphase cells (B) exhibit strong 3F3/2 staining at the kinetochores and spindle poles (arrowhead). At metaphase (C), 3F3/2 kinetochore labelling decreases significantly and is often undetectable. (D,E,F) S2 cells lysed in the absence of microcystin and then incubated with ATP plus microcystin (ATP+Mc). Kinetochores are strongly labelled with 3F3/2 antibody even at metaphase (E), but not at anaphase (F). (G) Dephosphorylated S2 cell (lysed with T-Mc) and incubated with ATP alone (ATP-Mc). 3F3/2 epitopes are not phosphorylated in the absence of microcystin. Scale bar: 5 µm.