Creatine kinase role in anaphase chromosome movement

Abstract

Creatine kinase catalyses the conversion of ADP and phosphoryl creatine into ATP and creatine. In skeletal muscle a non-mitochondrial isoenzyme of creatine kinase has a major role in regulating the energy supply for muscle contraction by maintaining the ATP pools at relatively constant levels^1,2. Recently, this enzyme has been localized by immunofluorescence techniques on intermediate filaments and stress fibres in interphase cells³ and in mitotic spindles of dividing tissue culture cell lines, including the PtK₁ cell line^4,5 and has been found to co-purify with spindles isolated from dividing sea urchin eggs⁶ and with muscle cell nuclei⁷. Here I have used permeabilized PtK₁ cells to investigate the possibility that creatine kinase may be involved in regulation of spindle energy metabolism by lysing cells in medium containing phosphoryl creatine. I find that spindle elongation will continue in these conditions, provided ADP is also present in the lysis medium. This finding is consistent with my previous demonstration that spindle elongation is the ATP-requiring step during anaphase^8,9 and is a direct demonstration that creatine kinase may have a role in mitosis analogous to that observed during skeletal muscle contraction.