Open Access

The effect of the lipid-binding site of the ankyrin-binding domain of erythroid β-spectrin on the properties of natural membranes and skeletal structures

  • Anna Chorzalska1,
  • Agnieszka Łach1,
  • Tomasz Borowik2,
  • Marcin Wolny1,
  • Anita Hryniewicz-Jankowska1,
  • Adam Kolondra1,
  • Marek Langner2, 3 and
  • Aleksander F. Sikorski1, 3Email author
Cellular & Molecular Biology LettersAn International Journal201015:12

https://doi.org/10.2478/s11658-010-0012-6

Received: 12 November 2009

Accepted: 10 March 2010

Published: 29 March 2010

Abstract

It was previously shown that the beta-spectrin ankyrin-binding domain binds lipid domains rich in PE in an ankyrin-dependent manner, and that its N-terminal sequence is crucial in interactions with phospholipids. In this study, the effect of the full-length ankyrin-binding domain of β-spectrin on natural erythrocyte and HeLa cell membranes was tested. It was found that, when encapsulated in resealed erythrocyte ghosts, the protein representing the full-length ankyrin-binding domain strongly affected the shape and barrier properties of the erythrocyte membrane, and induced partial spectrin release from the membrane, while truncated mutants had no effect. As found previously (Bok et al. Cell Biol. Int. 31 (2007) 1482–94), overexpression of the full-length GFP-tagged ankyrin-binding domain aggregated and induced aggregation of endogenous spectrin, but this was not the case with overexpression of proteins truncated at their N-terminus. Here, we show that the aggregation of spectrin was accompanied by the aggregation of integral membrane proteins that are known to be connected to spectrin via ankyrin, i.e. Na+K+ATP-ase, IP3 receptor protein and L1 CAM. By contrast, the morphology of the actin cytoskeleton remained unchanged and aggregation of cadherin E or N did not occur upon the overexpression of either full-length or truncated ankyrin-binding domain proteins. The obtained results indicate a substantial role of the lipid-binding part of the β-spectrin ankyrin-binding domain in the determination of the membrane and spectrin-based skeleton functional properties.

Key words

Spectrin-lipid interactionsAnkyrin-binding domainResealed ghostsMembrane skeleton propertiesTransmembrane protein aggregation

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