Characterization and mapping of the interaction between the cytoplasmic domain of band 3 and adducin

Taina Franco, Purdue University

Abstract

Two major bridges between the erythrocyte membrane bilayer and the cytoskeleton are believed to maintain structural integrity and flexibility of the cell: (1) the transmembrane protein band 3-ankyrin-β-spectrin, and (2) glycophorin C-protein 4.1- β-spectrin. Disruption of the first bridge leads to loss of membrane integrity and subsequently loss of membrane surface area. However, rupture of the glycophorin C-protein 4.1 interaction suggested that this linkage do not constitute a crucial role on membrane stability. Evidences have demonstrated the finding of a third bridge between band 3-adducin-actin/spectrin network. This new bridge directly links band 3 to the junctional complex. Here we reveal that this interaction is important to maintain the red blood cell membrane integrity. Additionally, we identified the adducin binding site on cdb3 using a novel technique that combined a cross-linking biotin label transfer and mass spectrometry. Both, α- and β-adducin interaction site on the cytoplasmic domain of band 3 were identified between residues 246-264. More importantly, mutation of two glutamic residues on the surface of this region leads to loss of adducin affinity to band 3. Identification of the interaction sites between these proteins will elucidate roles of both adducin and band 3 in the erythrocyte.

Degree

Ph.D.

Advisors

Low, Purdue University.

Subject Area

Biochemistry

COinS