Ankyrin recognizes both surface character and shape of the 14-15 di-repeat of beta-spectrin.
The spectrin-based cytoskeleton is critical for cell stability, membrane organization and membrane protein trafficking. At its core is the high-affinity complex between beta-spectrin and ankyrin. Defects in either of these proteins may cause hemolytic disease, developmental disorders, neurologic disease, and cancer. Crystal structures of the minimal recognition motifs of ankyrin and beta-spectrin have been determined and distinct recognition mechanisms proposed. One focused on the complementary surface charges of the minimal recognition motifs, whereas the other identified an unusual kink between beta-spectrin repeats and suggested a conformation-sensitive binding surface. Using isothermal titration calorimetry and site-directed mutagenesis, we demonstrate the primacy of the inter-repeat kink as the critical determinant underlying spectrin's ankyrin affinity. The clinical implications of this are discussed in light of recognized linker mutations and polymorphisms in the beta-spectrins.
La-Borde
Penelope J
PJ
University of Illinois at Chicago, Department of Biochemistry and Molecular Genetics, 900 S. Ashland Ave., MBRB 1170, Chicago, IL 60607, USA.
Stabach
Paul R
PR
Simonović
Ivana
I
Morrow
Jon S
JS
Simonović
Miljan
M
D017487:Ankyrins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011487:Protein Conformation; D012091:Repetitive Sequences, Nucleic Acid; D013049:Spectrin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D017487:Ankyrins; D013049:Spectrin