How does Reelin control neuronal migration and layer formation in the developing mammalian neocortex?

Area of Science:

• Neuroscience
• Developmental Biology
• Cell Biology

Background:

• The mammalian neocortex exhibits a layered structure formed via "inside-out" neuronal migration.
• Reelin is a well-known molecule essential for this "inside-out" pattern.
• The precise cellular and molecular roles of Reelin in layer formation remain largely undefined.

Purpose of the Study:

• To review and synthesize current knowledge on Reelin's functions in neuronal migration.
• To elucidate the mechanisms by which Reelin regulates neuron positioning and layer establishment.

Main Methods:

• This review synthesizes findings from various experimental studies on Reelin's role in neuronal migration.
• Analysis of molecular pathways and cellular behaviors influenced by Reelin.

Main Results:

• Reelin influences neuronal migration in at least two key steps: terminal translocation and regulation of cell polarity during migratory mode switching.
• Reelin activates integrin α5β1 and the nectin-afadin/N-cadherin system for translocation.
• Reelin promotes migration termination by degrading Dab1 and induces birth-date-dependent neuronal aggregation.

Conclusions:

• Reelin's functions in neuronal migration are multifaceted, impacting translocation, polarity, and aggregation.
• Reelin is hypothesized to control cell-adhesiveness by regulating cell adhesion molecules during neocortex development.