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Updated: Aug 11, 2026

Purification of the Dendritic Filopodia-rich Fraction
Published on: May 2, 2019
The polarity protein PAR-3 and TIAM1 cooperate in dendritic spine morphogenesis
1Center for Cell Signaling, Department of Microbiology, University of Virginia School of Medicine, Charlottesville, VA 22908-0577, USA. hz5a@virginia.edu
Abstract:
PAR-3 (partitioning-defective gene 3) is essential for cell polarization in many contexts, including axon specification. However, polarity proteins have not been implicated in later steps of neuronal differentiation, such as dendritic spine morphogenesis. Here, we show that PAR-3 is necessary for normal spine development in primary hippocampal neurons. Depletion of PAR-3 causes the formation of multiple filopodia- and lamellipodia-like dendritic protrusions - a phenotype similar to neurons expressing activated Rac. PAR-3 regulates spine formation by binding the Rac guanine nucleotide-exchange factor (GEF) TIAM1, and spatially restricting it to dendritic spines. Thus, a balance of PAR-3 and TIAM1 is essential to modulate Rac-GTP levels and to allow spine morphogenesis.
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