The Crumbs family of apical transmembrane proteins regulates apicobasal polarity via protein interactions with a conserved C-terminal sequence, ERLI. However, one of the mammalian Crumbs proteins, Crumbs3 (CRB3) has an alternate splice form with a novel C-terminal sequence ending in CLPI (CRB3-CLPI). We report that CRB3-CLPI localizes to the cilia membrane and a membrane compartment at the mitotic spindle poles. Knockdown of CRB3-CLPI leads to both a loss of cilia and a multinuclear phenotype associated with centrosomal and spindle abnormalities. Using protein purification, we find that CRB3-CLPI interacts with importin β-1 in a Ran-regulated fashion. Importin β-1 colocalizes with CRB3-CLPI during mitosis, and a dominant-negative form of importin β-1 closely phenocopies CRB3-CLPI knockdown. Knockdown of importin β-1 blocks targeting of CRB3-CLPI to the spindle poles. Our data suggest an expanded role for Crumbs proteins in polarized membrane targeting and cell division via unique interactions with importin proteins.
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30 July 2007
Article|
July 23 2007
A novel Crumbs3 isoform regulates cell division and ciliogenesis via importin β interactions
Vanessa Fogg,
Vanessa Fogg
1Department of Internal Medicine
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Xiao-Wei Chen,
Xiao-Wei Chen
3Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
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Chia-Jen Liu,
Chia-Jen Liu
1Department of Internal Medicine
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Ben Margolis
Ben Margolis
1Department of Internal Medicine
2Department of Biological Chemistry,
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Shuling Fan
1Department of Internal Medicine
Vanessa Fogg
1Department of Internal Medicine
Qian Wang
2Department of Biological Chemistry,
Xiao-Wei Chen
3Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
Chia-Jen Liu
1Department of Internal Medicine
Ben Margolis
1Department of Internal Medicine
2Department of Biological Chemistry,
Correspondence to Ben Margolis: [email protected]
Abbreviations used in this paper: EST, expressed sequence tag; shRNA, short hairpin RNA; wt, wild-type.
Received:
September 15 2006
Accepted:
July 02 2007
Online ISSN: 1540-8140
Print ISSN: 0021-9525
The Rockefeller University Press
2007
J Cell Biol (2007) 178 (3): 387–398.
Article history
Received:
September 15 2006
Accepted:
July 02 2007
Citation
Shuling Fan, Vanessa Fogg, Qian Wang, Xiao-Wei Chen, Chia-Jen Liu, Ben Margolis; A novel Crumbs3 isoform regulates cell division and ciliogenesis via importin β interactions . J Cell Biol 30 July 2007; 178 (3): 387–398. doi: https://doi.org/10.1083/jcb.200609096
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