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Updated: Jan 23, 2026

Monitoring Actin Disassembly with Time-lapse Microscopy
Published on: November 8, 2006
MARK2/Par1b kinase present at centrosomes and retraction fibres corrects spindle off-centring induced by actin
Madeleine Hart1, Ihsan Zulkipli2, Roshan Lal Shrestha2
11 School of Biological and Chemical Sciences, Queen Mary University of London , London , UK.
Abstract:
Tissue maintenance and development requires a directed plane of cell division. While it is clear that the division plane can be determined by retraction fibres that guide spindle movements, the precise molecular components of retraction fibres that control spindle movements remain unclear. We report MARK2/Par1b kinase as a novel component of actin-rich retraction fibres. A kinase-dead mutant of MARK2 reveals MARK2's ability to monitor subcellular actin status during interphase. During mitosis, MARK2's localization at actin-rich retraction fibres, but not the rest of the cortical membrane or centrosome, is dependent on its activity, highlighting a specialized spatial regulation of MARK2. By subtly perturbing the actin cytoskeleton, we reveal MARK2's role in correcting mitotic spindle off-centring induced by actin disassembly. We propose that MARK2 provides a molecular framework to integrate cortical signals and cytoskeletal changes in mitosis and interphase.
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