The functional organization and assembly of the axon initial segment.
Action potential initiation, modulation, and duration in neurons depend on a variety of Na+ and K+ channels that are highly enriched at the axon initial segment (AIS). The AIS also has high densities of cell adhesion molecules (CAMs), modulatory proteins, and a unique extracellular matrix (ECM). In contrast to other functional domains of axons (e.g. the nodes of Ranvier and axon terminals) whose development depends on the interactions with different cells (e.g. myelinating glia and postsynaptic cells), the recruitment and retention of AIS proteins is intrinsically specified through axonal cytoskeletal and scaffolding proteins. We speculate that the AIS has previously unappreciated forms of plasticity that influence neuronal excitability, and that AIS plasticity is regulated by the developmental or activity-dependent modulation of scaffolding protein levels rather than directly altering ion channel expression.
Ogawa
Yasuhiro
Y
Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. yogawa@cns.bcm.edu
Rasband
Matthew N
MN
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001369:Axons / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism
D015815:Cell Adhesion Molecules; D009419:Nerve Tissue Proteins