An, Xiuli and Zhang, Xihui and Debnath, Gargi and Baines, A.J. and Mohandas, Narla (2006) Phosphatidylinositol-4,5-biphosphate (PIP2) differentially regulates the interaction of human erythrocyte protein 4.1 (4.1R) with membrane proteins. Biochemistry, 45 (18). pp. 5725-5732. ISSN 0006-2960. (The full text of this publication is not available from this repository)
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Human erythrocyte protein 4.1 (4.1R) participates in organizing the plasma membrane by linking several surface-exposed transmembrane proteins to the internal cytoskeleton. In the present study, we characterized the interaction of 4.1R with phosphatidylinositol-4,5-bisphosphate (PIP2) and assessed the effect of PIP2 on the interaction of 4.1R with membrane proteins. We found that 4.1R bound to PIP2-containing liposomes through its N-terminal 30 kDa membrane-binding domain and PIP2 binding induced a conformational change in this domain. Phosphatidylinositol-4-phosphate (PIP) was a less effective inducer of this conformational change, and phosphatidylinositol (PI) and inositol-1,4,5-phosphate (IP3) induced no change. Replacement of amino acids K63,64 and K265,266 by alanine abolished the interaction of the membrane-binding domain with PIP2. Importantly, binding of PIP2 to 4.1R selectively modulated the ability of 4.1R to interact with its different binding partners. While PIP2 significantly enhanced the binding of 4.1R to glycophorin C (GPC), it inhibited the binding of 4.1R to band 3 in vitro. PIP2 had no effect on 4.1R binding to p55. Furthermore, GPC was more readily extracted by Triton X-100 from adenosine triphosphate (ATP)-depleted erythrocytes, implying that the GPC-4.1R interaction may be regulated by PIP2 in situ. These findings define an important role for PIP2 in regulating the function of 4.1R. Because 4.1R and its family members (4.1R, 4.1B, 4.1G, and 4.1N) are widely expressed and the PIP2-binding motifs are highly conserved, it is likely that the functions of other 4.1 proteins are similarly regulated by PIP2 in many different cell types.
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences > Cell & Developmental Biology Group|
|Depositing User:||Anthony Baines|
|Date Deposited:||05 Sep 2008 06:19|
|Last Modified:||17 Apr 2012 14:18|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/8625 (The current URI for this page, for reference purposes)|