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. Author manuscript; available in PMC: 2015 Jan 23.
Published in final edited form as: Mol Cell. 2014 Jan 23;53(2):179–192. doi: 10.1016/j.molcel.2013.12.022

Figure 1. Microtubules stabilize spindle assembly factors.

Figure 1

A. Microtubules protect spindle assembly factors from APC/CCdc20-dependent degradation in extracts. Extracts of prometaphase HeLa cells were subjected to p31comet to activate APC/CCdc20, and RanQ69L to release spindle assembly factors from importin inhibitors. As indicated, extracts were treated with taxol to stabilize microtubules. Control extracts were depleted of Cdc20, and the stability of endogenous substrates was monitored by immunoblotting. B. Microtubule-dependent stabilization of spindle assembly factors is reversible. Mitotic extracts were treated with taxol and RanQ69L. As indicated, nocodazole was added after 60min to depolymerize microtubules. C. Microtubules prevent APC/CCdh1-dependent degradation of spindle assembly factors. 35S-labeled HURP or cyclin B1 was added to G1-extracts of HeLa cells with active APC/CCdh1 and treated with taxol and RanQ69L. As control, the APC/CCdh1-inhibitor Emi1 was added, and substrate stability was monitored by autoradiography. See also Figure S1.