Restriction of 480/270-kD ankyrin G to axon proximal segments requires multiple ankyrin G-specific domains.

Published

Journal Article

AnkyrinG (-/-) neurons fail to concentrate voltage-sensitive sodium channels and neurofascin at their axon proximal segments, suggesting that ankyrinG is a key component of a structural pathway involved in assembly of specialized membrane domains at axon proximal segments and possibly nodes of Ranvier (Zhou, D., S. Lambert, D.L. Malen, S. Carpenter, L. Boland, and V. Bennett, manuscript submitted for publication). This paper addresses the mechanism for restriction of 270-kD ankyrinG to axon proximal segments by evaluation of localization of GFP-tagged ankyrinG constructs transfected into cultured dorsal root ganglion neurons, as well as measurements of fluorescence recovery after photobleaching of neurofascin- GFP-tagged ankyrinG complexes in nonneuronal cells. A conclusion is that multiple ankyrinG-specific domains, in addition to the conserved membrane-binding domain, contribute to restriction of ankyrinG to the axonal plasma membrane in dorsal root ganglion neurons. The ankyrinG-specific spectrin-binding and tail domains are capable of binding directly to sites on the plasma membrane of neuronal cell bodies and axon proximal segments, and presumably have yet to be identified docking sites. The serine-rich domain, which is present only in 480- and 270-kD ankyrinG polypeptides, contributes to restriction of ankyrinG to axon proximal segments as well as limiting lateral diffusion of ankyrinG-neurofascin complexes. The membrane-binding, spectrin-binding, and tail domains of ankyrinG also contribute to limiting the lateral mobility of ankyrinG-neurofascin complexes. AnkyrinG thus functions as an integrated mechanism involving cooperation among multiple domains heretofore regarded as modular units. This complex behavior explains ability of ankyrinB and ankyrinG to sort to distinct sites in neurons and the fact that these ankyrins do not compensate for each other in ankyrin gene knockouts in mice.

Full Text

Duke Authors

Cited Authors

  • Zhang, X; Bennett, V

Published Date

  • September 21, 1998

Published In

Volume / Issue

  • 142 / 6

Start / End Page

  • 1571 - 1581

PubMed ID

  • 9744885

Pubmed Central ID

  • 9744885

International Standard Serial Number (ISSN)

  • 0021-9525

Digital Object Identifier (DOI)

  • 10.1083/jcb.142.6.1571

Language

  • eng

Conference Location

  • United States