AnkyrinG. A new ankyrin gene with neural-specific isoforms localized at the axonal initial segment and node of Ranvier.
We have characterized a new ankyrin gene, expressed in brain and other tissues, that is subject to extensive tissue-specific alternative mRNA processing. The full-length polypeptide has a molecular mass of 480 kDa and includes a predicted globular head domain, with membrane- and spectrin-binding activities, as well as an extended "tail" domain. We term this gene ankyrinG based on its giant size and general expression. Two brain-specific isoforms of 480 kDa and 270 kDa were identified that contain a unique stretch of sequence highly enriched in serine and threonine residues immediately following the globular head domain. Antibodies against the serine-rich domain and spectrin-binding domain revealed labeling of nodes of Ranvier and axonal initial segments. Ankyrin-binding proteins also known to be localized in these specialized membrane domains include the voltage-dependent sodium channel, the sodium/potassium ATPase, sodium/calcium exchanger, and members of the neurofascin/L1 family of cell adhesion molecules. The neural-specific ankyrinG polypeptides are candidates to participate in maintenance/targeting of ion channels and cell adhesion molecules to nodes of Ranvier and axonal initial segments.
Kordeli
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E
Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710.
Lambert
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Bennett
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V
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D017487:Ankyrins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001369:Axons / Q000648:ultrastructure; D001483:Base Sequence; D002540:Cerebral Cortex / Q000737:chemistry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D005796:Genes; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011901:Ranvier's Nodes / Q000737:chemistry*; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
D017487:Ankyrins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger