PTEN couples Sema3A signalling to growth cone collapse

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Biology

Background:

• Glycogen synthase kinase-3 (GSK-3) signaling influences neuronal development and axon guidance.
• Semaphorin 3A (Sema3A) mediates growth cone collapse in sensory neurons, a process dependent on GSK-3 activation.
• Phosphatidylinositol 3-kinase (PI3K) and the tumor suppressor PTEN regulate GSK-3 activity via phosphatidylinositol 3,4,5-trisphosphate.

Purpose of the Study:

• To investigate the role of PTEN in Sema3A-mediated growth cone collapse.
• To elucidate the mechanism by which PTEN regulates GSK-3 signaling in response to Sema3A.

Main Methods:

• Investigated PTEN involvement in Sema3A-induced growth cone collapse.
• Examined the relationship between Sema3A, PI3K signaling, GSK-3 activation, and PTEN phosphatase activity.
• Assessed PTEN localization in sensory growth cones during axonal extension and after Sema3A exposure.

Main Results:

• Sema3A suppresses PI3K signaling, leading to GSK-3 activation dependent on PTEN's phosphatase activity.
• PTEN is enriched in axonal compartments and the central domain of growth cones, colocalizing with microtubules.
• Sema3A exposure causes rapid PTEN accumulation at the growth cone membrane, linking Sema3A signaling to collapse.

Conclusions:

• PTEN is essential for regulating GSK-3 signaling in response to Sema3A.
• Subcellular localization of PTEN is critical for controlling growth cone behavior.
• These findings reveal a novel mechanism for PTEN in mediating axon guidance cues.