Functional diversity among spectrin isoforms

Coleman, Thomas R.; Fishkind, Douglas J.; Mooseker, Mark S.; Morrow, Jon S.

doi:10.1002/cm.970120405

Cited by 115 publications

(56 citation statements)

References 234 publications

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“…Based on their similarities, we suggest that Drosophila ␣␤ H spectrin and vertebrate terminal web spectrins constitute a distinct class of apically directed spectrin isoforms. Both proteins are unusually large compared with other known ␤ spectrin subunits and both utilize an ␣ spectrin subunit found in other spectrin isoforms (Coleman et al, 1989;Dubreuil et al, 1990). In addition, both proteins are found in the apical region of epithelial cells.…”

Section: Discussionmentioning

confidence: 99%

Segregation of Two Spectrin Isoforms: Polarized Membrane-binding Sites Direct Polarized Membrane Skeleton Assembly

Dubreuil

Maddux

Grushko

et al. 1997

MBoC

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Spectrin isoforms are often segregated within specialized plasma membrane subdomains where they are thought to contribute to the development of cell surface polarity. It was previously shown that ankyrin and ␤ spectrin are recruited to sites of cell-cell contact in Drosophila S2 cells expressing the homophilic adhesion molecule neuroglian. Here, we show that neuroglian has no apparent effect on a second spectrin isoform (␣␤ H ), which is constitutively associated with the plasma membrane in S2 cells. Another membrane marker, the Na,K-ATPase, codistributes with ankyrin and ␣␤ spectrin at sites of neuroglian-mediated contact. The distributions of these markers in epithelial cells in vivo are consistent with the order of events observed in S2 cells. Neuroglian, ankyrin, ␣␤ spectrin, and the Na,K-ATPase colocalize at the lateral domain of salivary gland cells. In contrast, ␣␤ H spectrin is sorted to the apical domain of salivary gland and somatic follicle cells. Thus, the two spectrin isoforms respond independently to positional cues at the cell surface: in one case an apically sorted receptor and in the other case a locally activated cell-cell adhesion molecule. The results support a model in which the membrane skeleton behaves as a transducer of positional information within cells.

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Section: Discussionmentioning

confidence: 99%

Segregation of Two Spectrin Isoforms: Polarized Membrane-binding Sites Direct Polarized Membrane Skeleton Assembly

Dubreuil

Maddux

Grushko

et al. 1997

MBoC

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“…Moreover, elf is a cluster b-spectrin gene since its chromosomal locus is close to mouse brain b-spectrin (Spnb-2 or bSpIIS1). The phenomenon of resistance to evolutionary pressure (Coleman et al, 1989).…”

Section: Discussionmentioning

confidence: 99%

Elf3 encodes a novel 200-kD β-spectrin: role in liver development

et al. 1999

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b-spectrins are crucial for the maintenance of cell shape, the establishment of cell polarity, and the formation of distinct membrane domains. Our strategy for identifying genes important for hepatocyte polarity has been to utilize subtractive hybridization of early embryonic mouse cDNA liver libraries. As a result, we have cloned three isoforms of a novel b-spectrin elf (embryonic liver b-fodrin), and here we report the analysis of elf3, the longest isoform (8172 nt). ELF3 comprises 2154 residues with an overall similarity of 89.0% and 95.3% to mouse b-spectrin (bSpIIS1) at the nucleotide and amino acid level, respectively. ELF3 is characterized by an actinbinding domain, a long repeat domain, and a short regulatory domain remarkable for the absence of a PH domain. Linkage analysis reveals that elf3 maps to mouse chromosome 11 between D11Bir6 and D11Xrf477, a di erent chromosomal locus from that of the other four spectrin genes. Northern blot analysis utilizing an elf3 3'-UTR probe demonstrates an abundant 9.0-kb transcript in brain, liver, and heart tissues. Western blot with a polyclonal antibody against ELF identi®es a 200 kD protein in mouse liver, brain, kidney, and heart tissues. Immunohistochemical studies demonstrate ELF labeling of the basolateral or sinusoidal membranes surface as well as a granular cytoplasmic pattern in hepatocytes. Antisense studies utilizing cultured liver explants show a vital role of elf3 in hepatocyte di erentiation and intrahepatic bile duct formation. The di erential expression, tissue localization, and functional studies demonstrate the importance of elf3 in modulating interactions between various components of the cytoskeleton proteins controlling liver and bile duct development.

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“…Other proteins are also candidates to participate in spectrin-actin interactions including adducin (3), tropomyosin (4), and a tropomyosin-binding protein named tropomodulin (5). Spectrin and the erythrocyte membrane have been the subject of several recent reviews (6)(7)(8)(9)(10).…”

Section: Overview Ofthe Membrane Skeleton Ofhuman Erythrocytesmentioning

confidence: 99%

“…(c) Betarw, a specialized subunit associated with terminal web in the apical domain of intestinal epithelial cells and which is found in birds but not in mammals (29). BetaTw may lack an ankyrin recognition site based on in vitro assays (8 (29). Purkinje cells in the cerebellum that have betaR in their cell bodies and beta0 in axons (32,33).…”

Section: Overview Ofthe Membrane Skeleton Ofhuman Erythrocytesmentioning

confidence: 99%