Cm

Neuronal Migration II: Translocation of Organelles and Nucleus

Key structures

Function

Nucleus

Central organelle containing genetic material

Perinuclear cage

Network surrounding the nucleus

Centrisome

Microtubule organizing center

Microtubules

Cytoskeletal elements providing structural support

Leading process

Forward extension of the migrating neuron

Translocation of Organelle

Step 1: Initial Configuration

*Nucleus is contained within the perinuclear cage

*The centrosome is positioned between the nucleus and leading process

*Microtubules extend from the centrosome toward the leading process

*The entire structure is oriented in the direction of migration

Step 2: Centrosome Movement

•Mechanism: The centrosome moves forward first

•Key protein involved:  

•Dynein: Motor protein that moves toward the minus end of the Microtubules

•Lis1: Regulator of dynein activity

•These proteins are anchored to the plasma membrane

•The anchoring provides the force needed to pull the centrosome forward

Stage 3: Nuclear Translocation

•Dual Mechanisms:

•Pushing force: Myosin 2 squeezes actin at the rear of the nucleus

•Pulling force: Dynein, Lis1, and NudE/Nudel proteins transport the nucleus forward

•The nucleus follows the centrosome's path

•The perinuclear cage maintains nuclear integrity during movement

Protein Interactions in Neuronal Migration

Protein

Function

Location

Interaction Partners

Dynein

Motor Protein

Plasma membrane, Microtubules

Lis1, NudE/Nudel

Lis1

Dynein regulator

Dynein, NudE/Nudel

Myosin 2

Motor Protein

Rear of nucleus

Actin

Nude/Nudel

Dynein cofactor Associated with Dynein

Dynein,Lis1