The effect of the lipid-binding site of the ankyrin-binding domain of erythroid beta-spectrin on the properties of natural membranes and skeletal structures.
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 beta-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 beta-spectrin ankyrin-binding domain in the determination of the membrane and spectrin-based skeleton functional properties.
Chorzalska
Anna
A
University of Wroclaw, Poland.
Lach
Agnieszka
A
Borowik
Tomasz
T
Wolny
Marcin
M
Hryniewicz-Jankowska
Anita
A
Kolondra
Adam
A
Langner
Marek
M
Sikorski
Aleksander F
AF
D008841:Actin Cytoskeleton / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism; D017487:Ankyrins / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D015820:Cadherins / Q000378:metabolism; D003599:Cytoskeleton; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013049:Spectrin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D000199:Actins; D017487:Ankyrins; D015820:Cadherins; D053496:Inositol 1,4,5-Trisphosphate Receptors; D039842:Neural Cell Adhesion Molecule L1; D011994:Recombinant Proteins; D013049:Spectrin; D000254:Sodium-Potassium-Exchanging ATPase