FUNCTIONAL STUDY OF HMMR IN REGULATING MICROTUBULE DYNAMICS AND CHROMOSOME MOVEMENT

Abstract

Accurate segregation of chromosomes during anaphase relies on central spindle and its regulators. The newly raised concept of central spindle, the bridging fiber, shows that sliding of antiparallel microtubules within the fiber promotes chromosome segregation. However, the regulators of the bridging fiber and regulatory mechanism on MTs sliding remain largely unknown. In this study, we identify the non-motor microtubule-associated protein HMMR, as a novel regulator of the bridging fiber, and determine its regulation of MTs sliding within the fiber by cooperating with HSET. Our results reveal that depletion of HMMR causes an inhibitory effect on MTs sliding within the bridging fiber and disrupts the force uniformity on the k-fibers, by suppressing the dynamics of HSET which functions in transiting the force from sliding of bridging MTs to k-fiber.