PTEN Regulates Dendritic Arborization by Decreasing Microtubule Polymerization Rate.

Area of Science:

• Neuroscience
• Cell Biology
• Genetics

Background:

• Phosphatase and tensin homolog (PTEN) is a key negative regulator of the PI3K/Akt/mTOR pathway.
• Loss-of-function PTEN mutations are linked to macrocephaly and autism spectrum disorder (ASD).
• PTEN loss in neurons causes somal hypertrophy, aberrant migration, and dendritic overgrowth.

Purpose of the Study:

• To investigate the mechanism of dendritic overgrowth in PTEN-deficient neurons.
• To examine the impact of PTEN loss on microtubule (MT) dynamics.
• To assess the therapeutic potential of targeting MT polymerization.

Main Methods:

• Utilized retroviral infection and transfection to manipulate PTEN expression in neurons.
• Tagged the plus-end MT binding protein, end-binding protein 3 (EB3), to study MT dynamics.
• Assessed dendritic growth, MT polymerization rates, and spatial memory in Pten knock-out (KO) and wild-type (WT) mice.

Main Results:

• Pten KO neurons exhibited increased process sprouting and higher MT polymerization rates in growth cones compared to WT neurons.
• Reducing MT polymerization rate in Pten KO neurons normalized dendritic overgrowth in vitro and in vivo.
• Inhibition of MT polymerization rescued dendritic overgrowth and improved spatial memory performance in Pten KO mice.

Conclusions:

• Increased microtubule (MT) polymerization is a key factor in PTEN loss-dependent dendritic overgrowth.
• Targeting MT polymerization offers a potential therapeutic strategy for conditions associated with PTEN loss, such as ASD.
• PTEN may regulate neuronal growth through parallel control of protein synthesis and cytoskeletal polymerization.