期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1991
卷号：88
期号：12
页码：5222-5226
DOI：10.1073/pnas.88.12.5222
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Protein 4.1 was initially characterized as a protein that regulates cytoskeletal assembly in erythrocytes. However, recent studies have shown that protein 4.1 is ubiquitous in mammalian cells. Here, we show that protein 4.1 is phosphorylated on tyrosine by the epidermal growth factor receptor (EGFR) tyrosine kinase. The phosphorylation site has been localized to the 8-kDa domain, which has one tyrosine, tyrosine-418. The 8-kDa region is required for the assembly of the spectrin/actin complex, and phosphorylation by EGFR reduced the ability of protein 4.1 to promote the assembly of the spectrin/actin/protein 4.1 ternary complex. Immunoblotting with anti-phosphotyrosine antibodies showed that purified protein 4.1 contained phosphorylated tyrosine, and this increased upon phosphorylation by EGFR. This suggests that tyrosine phosphorylation of protein 4.1 occurs in vivo and may be functionally significant. The tyrosine phosphorylation site is in the center of a sequence motif that is expressed by a differentiation-specific splicing mechanism.
