ladder for cortical nerve cells to climb during migration

[image]

neural crest cells

• derivatives
• result of defective migration
• major disease connection

cells near neural folds

• sensory neurons, autonomic neurons, pigment skin cells, connctive tissue of head and heart
• Hirschprung's Disease, craniofacial malformations, heart and adrenal malformations
• malignant melanoma[image]

1. protrusion of leading edge
2. adhesion
3. tail lets go, shift by contraction[image]

F-actin: actin filaments

G-actin: globular actin

F forms when concentration of G exceeds its critical concentration

• asymmetrical polymers
• polarized: + end and - end (polymerizes at +)
• pushes out leading edge to drive protrusion of cell

• motor molecule that pulls actin filaments
• hydrolize ATP to make mechanical force (contraction)
• moves the actin towards the leading edge after adhesion behind releases

• protrusion: assembling of F-actin
• deprotrusion: myosin II pulls F-actin towards leading edge
• motor molecule forces are responsible for pulling organelles forward to advance the cell as a whole

tubulin dimer polymers requiring GTP

polarity: plus end GTP, minus end GDP

dynamic instability: plus end can grow and shrink

track for organelle transport

1. leading process extension and adhesion
2. centrosome advance
3. nuclear translocation[image]