Molecular analysis of insertion/deletion mutations in protein 4.1 in elliptocytosis: I. Biochemical identification of rearrangements in the spectrin/actin binding domain and functional characterizations

S. L. Marchesi, J. Conboy, P. Agre, J. T. Letainger, V. T. Marchesi, D. W. Speicher, Narla Mohandas

Research output: Contribution to journalArticle

Abstract

Protein 4.1 (80 kD) interacts with spectrin and short actin filaments to form the erythrocyte membrane skeleton. Mutations of spectrin and protein 4.1 are associated with elliptocytosis or spherocytosis and anemia of varying severity. We analyzed two mutant protein 4.1 molecules associated with ellip-tocytosis: a high molecular weight 4.1 (95 kD) associated with mild elliptocytosis without anemia, and a low molecular weight 4.1 (two species at 68 and 65 kD) associated with moderate elliptocytosis and anemia. 4.195 was found to contain a ∼ 15-kD insertion adjacent to the spectrin/actin binding domain comprised, at least in part, of repeated sequence. 4.168/65 was found to lack the entire spectrin-actin binding domain. The mechanical stability of erythrocyte membranes containing 4.195 was identical to that of normal membranes, consistent with the presence of an intact spectrin-actin binding domain in protein 4.1. In contrast, membranes containing 4.168/65 have markedly reduced mechanical stability as a result of deleting the spectrin-actin binding domain. The mechanical stability of these membranes was improved following reconstitution with normal 4.1. These studies have thus enabled us to establish the importance of the spectrin-actin binding domain in regulating the mechanical stability of the erythrocyte membrane.

Original languageEnglish (US)
Pages (from-to)516-523
Number of pages8
JournalJournal of Clinical Investigation
Volume86
Issue number2
DOIs
StatePublished - Aug 1990
Externally publishedYes

Keywords

  • Elliptocytosis
  • Erythrocytes
  • Mutations
  • Protein 4.1

ASJC Scopus subject areas

  • Medicine(all)

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