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Identification of the spectrin subunit and domains required for formation of spectrin/adducin/actin complexes.

Publication ,  Journal Article
Li, X; Bennett, V
Published in: J Biol Chem
June 28, 1996

Adducin is an actin-binding protein that has been proposed to function as a regulated assembly factor for the spectrin/actin network. This study has addressed the question of the subunit and domains of spectrin required for formation of spectrin/adducin/actin complexes in in vitro assays. Quantitative evidence is presented that the beta-spectrin N-terminal domain plus the first two alpha-helical domains are required for optimal participation of spectrin in spectrin/adducin/actin complexes. The alpha subunit exhibited no detectable activity either alone or following association with beta-spectrin. The critical domains of beta-spectrin involved in complex formation were determined using recombinant proteins expressed in bacteria. The N-terminal domain (residues 1-313) of beta-spectrin associated with F-actin with a Kd of 26 microM, and promoted adducin binding to F-actin with half-maximal activation at 110 nM. Addition of the first alpha-helical domain (residues 1-422) lowered the Kdfor F-actin by 4-fold to 6 microM, but also reduced the capacity by 3-fold and had no effect on interaction with adducin. Further addition of the second alpha-helical domain (residues 1-528) did not alter binding to F-actin but resulted in a 2-fold increased activity in promoting adducin binding with half-maximal activation at 50 nM. Addition of up to eight additional alpha-helical domains (residues 1-1388) resulted in no further change in F-actin binding or association with adducin. These results demonstrate an unanticipated role of the first repeat of beta-spectrin in actin binding activity and of the second repeat in association with adducin/actin, and imply the possibility of an extended contact between adducin, spectrin, and actin involving several actin subunits.

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Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

June 28, 1996

Volume

271

Issue

26

Start / End Page

15695 / 15702

Location

United States

Related Subject Headings

  • Structure-Activity Relationship
  • Spectrin
  • Rabbits
  • Protein Binding
  • Macromolecular Substances
  • Chickens
  • Cattle
  • Calmodulin-Binding Proteins
  • Biochemistry & Molecular Biology
  • Animals
 

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Li, X., & Bennett, V. (1996). Identification of the spectrin subunit and domains required for formation of spectrin/adducin/actin complexes. J Biol Chem, 271(26), 15695–15702. https://doi.org/10.1074/jbc.271.26.15695
Li, X., and V. Bennett. “Identification of the spectrin subunit and domains required for formation of spectrin/adducin/actin complexes.J Biol Chem 271, no. 26 (June 28, 1996): 15695–702. https://doi.org/10.1074/jbc.271.26.15695.
Li, X., and V. Bennett. “Identification of the spectrin subunit and domains required for formation of spectrin/adducin/actin complexes.J Biol Chem, vol. 271, no. 26, June 1996, pp. 15695–702. Pubmed, doi:10.1074/jbc.271.26.15695.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

June 28, 1996

Volume

271

Issue

26

Start / End Page

15695 / 15702

Location

United States

Related Subject Headings

  • Structure-Activity Relationship
  • Spectrin
  • Rabbits
  • Protein Binding
  • Macromolecular Substances
  • Chickens
  • Cattle
  • Calmodulin-Binding Proteins
  • Biochemistry & Molecular Biology
  • Animals