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Updated: Sep 22, 2025

Aip1p Dynamics Are Altered by the R256H Mutation in Actin
Published on: July 30, 2014
Shielding of actin by the endoplasmic reticulum impacts nuclear positioning
Cátia Silva Janota1, Andreia Pinto1,2, Anna Pezzarossa1,3
1Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
Abstract:
Nuclear position is central to cell polarization, and its disruption is associated with various pathologies. The nucleus is moved away from the leading edge of migrating cells through its connection to moving dorsal actin cables, and the absence of connections to immobile ventral stress fibers. It is unclear how these asymmetric nucleo-cytoskeleton connections are established. Here, using an in vitro wound assay, we find that remodeling of endoplasmic reticulum (ER) impacts nuclear positioning through the formation of a barrier that shields immobile ventral stress fibers. The remodeling of ER and perinuclear ER accumulation is mediated by the ER shaping protein Climp-63. Furthermore, ectopic recruitment of the ER to stress fibers restores nuclear positioning in the absence of Climp-63. Our findings suggest that the ER mediates asymmetric nucleo-cytoskeleton connections to position the nucleus.
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