Article

Apical-basal polarity in Drosophila neuroblasts is independent of vesicular trafficking.

Stammzellbiologie, Abteilung Anatomie und Zellbiologie, Georg-August-Universität Göttingen, 37077 Göttingen, Germany.
Molecular biology of the cell (impact factor: 5.98). 09/2011; 22(22):4373-9. DOI:10.1091/mbc.E11-03-0219
Source: PubMed

ABSTRACT The possession of apical-basal polarity is a common feature of epithelia and neural stem cells, so-called neuroblasts (NBs). In Drosophila, an evolutionarily conserved protein complex consisting of atypical protein kinase C and the scaffolding proteins Bazooka/PAR-3 and PAR-6 controls the polarity of both cell types. The components of this complex localize to the apical junctional region of epithelial cells and form an apical crescent in NBs. In epithelia, the PAR proteins interact with the cellular machinery for polarized exocytosis and endocytosis, both of which are essential for the establishment of plasma membrane polarity. In NBs, many cortical proteins show a strongly polarized subcellular localization, but there is little evidence for the existence of distinct apical and basolateral plasma membrane domains, raising the question of whether vesicular trafficking is required for polarization of NBs. We analyzed the polarity of NBs mutant for essential regulators of the main exocytic and endocytic pathways. Surprisingly, we found that none of these mutations affected NB polarity, demonstrating that NB cortical polarity is independent of plasma membrane polarity and that the PAR proteins function in a cell type-specific manner.

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Keywords

apical crescent
 
apical junctional region
 
apical-basal polarity
 
atypical protein kinase C
 
cell type-specific manner
 
cell types
 
cellular machinery
 
common feature
 
complex localize
 
essential regulators
 
evolutionarily conserved protein complex
 
NB cortical polarity
 
NB polarity
 
PAR proteins function
 
PAR proteins interact
 
plasma membrane polarity
 
polarized exocytosis
 
polarized subcellular localization
 
scaffolding proteins Bazooka/PAR-3
 
so-called neuroblasts
 

Nils Halbsgut