A tight grip on differentiation: Nuclear constriction by microtubules regulates hematopoietic stem cells.

Maintenance of the mature blood cells requires controlled cell fate decisions by hematopoietic stem and progenitor cells (HSPCs). While our knowledge of the gene expression changes that facilitate differentiation has made a leap forward, less is known about the cellular triggers that induce them. Biedzinski et al (2020) now uncover a new intracellular mechanism that drives myeloid differentiation: Microtubule bundles squeeze the nucleus of HSPCs and form large invaginations, thus causing changes in chromatin organization. These microtubule-induced nuclear shape changes result in gene expression profiles that favor myeloid differentiation.