DnaJB6 is a RanGTP-regulated protein required for microtubule organization during mitosis

Bipolar spindle organization is essential for the faithful segregation of chromosomes during cell division. This organization relies on the collective activities of motor proteins. The minus-end-directed dynein motor complex generates spindle inward forces and plays a major role in spindle pole focusing. The dynactin complex regulates many dynein functions, increasing its processivity and force production. Here, we show that DnaJB6 is a novel RanGTP-regulated protein. It interacts with the dynactin subunit p150Glued (also known as DCTN1) in a RanGTP-dependent manner specifically in M-phase, and promotes spindle pole focusing and dynein force generation. Our data suggest a novel mechanism by which RanGTP regulates dynein activity during M-phase.We acknowledge the Spanish Ministry of Economy, Industry and Competitiveness (Ministerio de Economía y Competitividad) to the EMBL partnership and support of the Spanish Ministry of Economy and Competitiveness, ‘Centro de Excelencia Severo Ochoa’ as well as support of the CERCA Programme/Generalitat de Catalunya. M.R. was supported by a FPI fellowship from the Spanish Ministry of Economy BES-2013-064601. Work in the Vernos laboratory was supported by grants from the Spanish Ministry of Economy and Competitiveness I+D (grants BFU2012-37163 and BFU2015-68726-P). Deposited in PMC for immediate release