NET1 mRNA localization to the midbody is required for ARP2/3-dependent initiation of mitotic abscission

Abstract

The recruitment and activation of abscission machinery following mitosis is tightly regulated in time and space, yet the mechanisms controlling this process are poorly understood. We find that RNA localization and local translation at the midbody regulates when and where abscission-regulating proteins are expressed. The 3'UTR of NET1 mRNA contains an element that is necessary and sufficient for RNA targeting to the midbody. Mislocalization of NET1 mRNA results in a loss of NET1 protein, a Rho family GEF, throughout the intercellular bridge as well as slower cell proliferation and delayed abscission. This leads to a loss of Arp2/3 at the abscission site and is dependent upon NET1 binding to Rho family GTPases. These findings establish midbody RNA localization and local translation as a key layer of regulation over abscission timing and identify a role for NET1 as a regulator of Arp2/3-mediated branched actin accumulation at the abscission site.