Inhibition of erythrocyte membrane shape change by band 3 cytoplasmic fragment

✍ Scribed by David P. Carter; Grant Fairbanks

• Book ID: 102878496
• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: English
• Weight: 537 KB
• Volume: 24
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240240408

✦ Synopsis

The ATP-dependent transformation of crenated white human erythrocyte ghosts into smoothed disc and cup forms is inhibited by the soluble 4045-kilodalton ( m a ) cytoplasmic portion of the major transmembrane protein, band 3 . The band 3 fragment was prepared by chymotryptic treatment of inverted vesicles stripped of peripheral proteins. When present at 20.2 mg per mg membrane protein (ie, 2 2 mol fragment per mol endogenous band 3 ) , the fragment significantly reduced the rate of shape change but did not alter the proportion of membranes that were ultimately converted into smoothed forms (>90%). The inhibitory activity of the fragment could not be attributed to contamination of the fragment preparation by actin or proteolytic enzymes. ATP-independent shape transformation was not inhibited. The band 3 fragment may compete with endogenous, intact band 3 for an association with the spectrin-actin network required for ATP-dependent smoothing of crenated membranes.