Ubiquitination of red blood cell α-spectrin does not affect heterodimer formation

✍ Scribed by Mahnoush H. Riahi; David G. Kakhniashvili; Steven R. Goodman

• Book ID: 101434459
• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 185 KB
• Volume: 78
• Category: Article
• ISSN: 0361-8609
• DOI: 10.1002/ajh.20282

✦ Synopsis

Abstract

Erythrocyte α‐spectrin is ubiquitinated in repeats α20/α21, which also represents the nucleation site for contact with the β subunit which leads to heterodimer formation by a zippering mechanism. In this study we have determined the second‐order rate constant for association of ubiquitinated α′‐spectrin, nonubiquitinated α‐spectrin, and β‐spectrin into the α′β or αβ heterodimer. The rate constant for incorporation of monomers into heterodimers at 37°C were (5.181 ± 0.001) × 10^5^ M^−1^ sec^−1^ for total α‐spectrin (α + α′), (5.121 ± 0.001) × 10^5^ M^−1^ sec^−1^ for α′‐spectrin, and (5.178 ± 0.003) × 10^5^ M^−1^ sec^−1^ for β‐spectrin. We conclude that ubiquitination of α‐spectrin does not regulate heterodimer formation. Am. J. Hematol. 78:281–287, 2005. © 2005 Wiley‐Liss, Inc.