MARCKS modulates radial progenitor placement, proliferation and organization in the developing cerebral cortex

Development. 2009 Sep;136(17):2965-75. doi: 10.1242/dev.036616.

Abstract

The radial glial cells serve as neural progenitors and as a migratory guide for newborn neurons in the developing cerebral cortex. These functions require appropriate organization and proliferation of the polarized radial glial scaffold. Here, we demonstrate in mice that the myristoylated alanine-rich C-kinase substrate protein (MARCKS), a prominent cellular substrate for PKC, modulates radial glial placement and expansion. Loss of MARCKS results in ectopic collection of mitotically active radial progenitors away from the ventricular zone (VZ) in the upper cerebral wall. Apical restriction of key polarity complexes [CDC42, beta-catenin (CTNNB1), N-cadherin (CDH2), myosin IIB (MYOIIB), aPKCzeta, LGL, PAR3, pericentrin, PROM1] is lost. Furthermore, the radial glial scaffold in Marcks null cortex is compromised, with discontinuous, non-radial processes apparent throughout the cerebral wall and deformed, bulbous, unbranched end-feet at the basal ends. Further, the density of radial processes within the cerebral cortex is reduced. These deficits in radial glial development culminate in aberrant positioning of neurons and disrupted cortical lamination. Genetic rescue experiments demonstrate, surprisingly, that phosphorylation of MARCKS by PKC is not essential for the role of MARCKS in radial glial cell development. By contrast, the myristoylation domain of MARCKS needed for membrane association is essential for MARCKS function in radial glia. The membrane-associated targeting of MARCKS and the resultant polarized distribution of signaling complexes essential for apicobasal polarity may constitute a critical event in the appropriate placement, proliferation and organization of polarized radial glial scaffold in the developing cerebral cortex.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Biomarkers / metabolism
  • Cell Membrane / metabolism
  • Cell Polarity
  • Cell Proliferation*
  • Cerebral Cortex* / cytology
  • Cerebral Cortex* / embryology
  • Cerebral Cortex* / growth & development
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Knockout
  • Myristoylated Alanine-Rich C Kinase Substrate
  • Neuroglia* / cytology
  • Neuroglia* / physiology
  • Protein Kinase C / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Stem Cells* / cytology
  • Stem Cells* / physiology

Substances

  • Biomarkers
  • Intracellular Signaling Peptides and Proteins
  • Marcks protein, mouse
  • Membrane Proteins
  • Recombinant Fusion Proteins
  • Myristoylated Alanine-Rich C Kinase Substrate
  • Protein Kinase C