Scribble, Erbin, and Lano redundantly regulate epithelial polarity and apical adhesion complex

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• The basolateral protein Scribble (Scrib) is vital for epithelial apicobasal polarity (ABP) in Drosophila.
• Its conserved function in mammals remained unclear due to compensatory roles of other LAP proteins.

Purpose of the Study:

• To investigate the conserved function of Scribble (Scrib) in mammalian epithelial apicobasal polarity (ABP).
• To elucidate the compensatory mechanisms involving LAP proteins Erbin and Lano in mammalian ABP.

Main Methods:

• Generated a combined knockout of Scrib, Erbin, and Lano in mammalian cells.
• Analyzed cell-cell junctions, cytoskeleton organization, and protein localization.
• Performed structure-function analysis of the conserved

Main Results:

• Combined knockout of Scrib, Erbin, and Lano disrupted cell-cell junctions and cytoskeleton.
• Significant mislocalization of apical (Par6, aPKC, Pals1) and basolateral (Llgl1, Llgl2) proteins observed.
• The conserved

Conclusions:

• The compensatory functions of Erbin and Lano mask Scrib's role in mammalian ABP.
• The conserved LU region, particularly LAPSDb and LAPSDa domains, is crucial for basolateral targeting and identity.
• Llgl mislocalization is less critical for the Scrib ABP phenotype in mammals compared to Drosophila.