Par1b Induces Asymmetric Inheritance of Plasma Membrane Domains via LGN-Dependent Mitotic Spindle Orientation in Proliferating Hepatocytes

The development and maintenance of polarized epithelial tissue requires a tightly controlled orientation of mitotic cell division relative to the apical polarity axis. hepatocytes display a unique polarized architecture. we demonstrate that mitotic hepatocytes asymmetrically segregate their apical plasma membrane domain to the nascent daughter cells. the non-polarized nascent daughter cell can form a de novo apical domain with its new neighbor. this asymmetric segregation of apical domains is facilitated by a geometrically distinct apicolateral subdomain of the lateral surface present in hepatocytes. the polarity protein partitioning-defective 1/microtubule-affinity regulating kinase 2 (par1b/mark2) translates this positional landmark to cortical polarity by promoting the apicolateral accumulation of leu-gly-asn repeat-enriched protein (lgn) and the capture of nuclear mitotic apparatus protein (numa)-positive astral microtubules to orientate the mitotic spindle. proliferating hepatocytes thus display an asymmetric inheritance of their apical domains via a mechanism that involves par1b and lgn,which we postulate serves the unique tissue architecture of the developing liver parenchyma. © 2013 slim et al.