BMPR-2 gates activity-dependent stabilization of primary dendrites during mitral cell remodeling

Area of Science:

• Neuroscience
• Molecular Biology
• Developmental Biology

Background:

• Developing neurons undergo extensive neurite remodeling.
• Mitral cells in the olfactory bulb initially extend multiple primary dendrites, then stabilize one.
• Mechanisms for selective dendrite stabilization are not fully understood.

Purpose of the Study:

• To identify key regulators of selective primary dendrite stabilization in developing mitral cells.
• To elucidate the molecular mechanisms by which BMPR-2 controls dendrite remodeling.

Main Methods:

• CRISPR-Cas9-based knockout screening.
• In utero electroporation.
• Genetic and Förster Resonance Energy Transfer (FRET) imaging experiments.

Main Results:

• BMPR-2 was identified as a crucial regulator for selective dendrite stabilization.
• BMPR-2 inhibits LIMK in the absence of ligands, promoting dendrite destabilization.
• Ligand-bound BMPR-2 stabilizes dendrites by releasing LIMK, which is activated by NMDARs via Rac1 and promotes F-actin formation.

Conclusions:

• Selective primary dendrite stabilization in mitral cells is controlled by BMPR-2.
• BMPR-2 integrates molecular cues (BMP ligands) and neuronal activity (NMDARs) to ensure proper dendrite remodeling.
• This study reveals a novel mechanism for activity-dependent dendrite stabilization.