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Cell 2019 Feb 07;1764:805-815.e8. doi: 10.1016/j.cell.2018.12.001.
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Importin α Partitioning to the Plasma Membrane Regulates Intracellular Scaling.

Brownlee C , Heald R .

Early embryogenesis is accompanied by reductive cell divisions requiring that subcellular structures adapt to a range of cell sizes. The interphase nucleus and mitotic spindle scale with cell size through both physical and biochemical mechanisms, but control systems that coordinately scale intracellular structures are unknown. We show that the nuclear transport receptor importin α is modified by palmitoylation, which targets it to the plasma membrane and modulates its binding to nuclear localization signal (NLS)-containing proteins that regulate nuclear and spindle size in Xenopus egg extracts. Reconstitution of importin α targeting to the outer boundary of extract droplets mimicking cell-like compartments recapitulated scaling relationships observed during embryogenesis, which were altered by inhibitors that shift levels of importin α palmitoylation. Modulation of importin α palmitoylation in human cells similarly affected nuclear and spindle size. These experiments identify importin α as a conserved surface area-to-volume sensor that scales intracellular structures to cell size.

PubMed ID: 30639102
PMC ID: PMC6368448
Article link: Cell
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: ctnnb1 h2bc21 kif22 kif2a kifc1 kpna1 lmnb3 lypla1 lyplal1 porcn rpe tpx2
Antibodies: GFP Ab21 Histone H2B Ab10 Kif22 Ab1 Kif2a Ab1 Kifc1 Ab1 Lyplal1 Ab1 Porcn Ab1 Tpx2 Ab1

Article Images: [+] show captions
References [+] :
Bird, RanGTP and CLASP1 cooperate to position the mitotic spindle. 2013, Pubmed