Transition from metaphase to anaphase is accompanied by local changes in cytoplasmic free calcium in Pt K2 kidney epithelial cells.
We have used a Ca2+-sensitive dye, fura-2, to investigate the role of Ca2+ during mitosis in Pt K2 epithelial cells. The concentration of cytoplasmic free calcium, [Ca2+]i, increased 2-fold between metaphase and anaphase. Digital image analysis revealed two patterns of [Ca2+]i localization during anaphase. In half of the anaphase cells, the increase in [Ca2+]i was greatest in the region near the spindle poles and decreased radially. In the other anaphase cells, there was a ring of high [Ca2+]i in the cytoplasm, surrounding an area of low [Ca2+]i in the spindle midzone. Although the reason for the different patterns is not known, peak [Ca2+]i in both cases was sufficient to maintain a 2- to 6-fold gradient in [Ca2+]i from the polar region to the midzone. [Ca2+]i gradients may thus regulate spindle microtubule equilibria and directed chromosome movement during mitosis.
Ratan
R R
RR
Shelanski
M L
ML
Maxfield
F R
FR
D000705:Anaphase; D000818:Animals; D001572:Benzofurans; D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000502:physiology; D003593:Cytoplasm / Q000032:analysis; D004847:Epithelial Cells; D016257:Fura-2; D007668:Kidney / Q000166:cytology; D007614:Macropodidae; D008677:Metaphase; D008941:Spindle Apparatus / Q000032:analysis
D001572:Benzofurans; D002147:Calmodulin; D002118:Calcium; D016257:Fura-2