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Nuclear fallout provides a new link between aPKC and polarized cell trafficking
Francisco J Calero-Cuenca1, José Manuel Espinosa-Vázquez1, Miguel Reina-Campos2
1CABD, CSIC/JA/UPO, Campus Universidad Pablo de Olavide, Ctra. De Utrera Km. 1, Seville, 41013, Spain.
BMC Biology
|April 20, 2016
Summary
Nuclear Fallout (Nuf) links Rab11-GTPase trafficking to microtubule motors and aPKC kinase, crucial for cell polarity. Nuf phosphorylation by aPKC regulates protein distribution, impacting recycling endosome delivery and epithelial cell polarity.
Area of Science:
- Cell Biology
- Molecular Biology
- Epithelial Biology
Background:
- Cell polarity is vital for tissue function, arising from protein localization and cellular component trafficking.
- The interplay between molecules regulating these processes remains poorly understood.
Purpose of the Study:
- To elucidate the molecular link between Nuclear Fallout (Nuf) and atypical Protein Kinase C (aPKC) in cell polarity.
- To investigate the role of Nuf-aPKC interaction in Recycling Endosome (RE) trafficking and polarity establishment.
Main Methods:
- Investigated the interaction and phosphorylation of Nuf by aPKC.
- Utilized aPKC and nuf mutants to assess subcellular distribution of Nuf and Rab11.
- Examined aPKC localization dynamics under conditions of blocked exocytosis (exocyst-sec mutants).
Main Results:
- aPKC phosphorylates Nuf, altering its subcellular distribution.
- Nuf and Rab11 accumulate apically in aPKC mutants, indicating disrupted RE delivery.
- aPKC localization is dynamic; exocytosis inhibition causes intracellular accumulation, while nuf mutants show reduced apical aPKC, suggesting recycling-dependent maintenance.
Conclusions:
- Established a direct molecular link between aPKC and Nuf, where aPKC-mediated Nuf phosphorylation modifies its distribution.
- Proposed a regulatory loop where Nuf promotes aPKC apical recycling to achieve sufficient active aPKC levels.
- Provided novel insights into the integration of cell polarity regulation and traffic control in epithelial cells.
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