We have identified the human homologue of a regulatory cofactor of Na+ -H+ exchanger (NHE-RF) as a novel interactor for merlin, the neurofibromatosis 2 tumor suppressor protein. NHE-RF mediates protein kinase A regulation of Na+ -H+ exchanger NHE3 to which it is thought to bind via one of its two PDZ domains. The carboxyl-terminal region of NHE-RF, downstream of the PDZ domains, interacts with the amino-terminal protein 4.1 domain-containing segment of merlin in yeast two-hybrid assays. This interaction also occurs in affinity binding assays with full-length NHE-RF expressed in COS-7 cells. NHE-RF binds to the related ERM proteins, moesin and radixin. We have localized human NHE-RF to actin-rich structures such as membrane ruffles, microvilli, and filopodia in HeLa and COS-7 cells, where it co-localizes with merlin and moesin. These findings suggest that hNHE-RF and its binding partners may participate in a larger complex (one component of which might be a Na+ -H+ exchanger) that could be crucial for the actin filament assembly activated by the ERM proteins and for the tumor suppressor function of merlin.
CITATION STYLE
Murthy, A., Gonzalez-Agosti, C., Cordero, E., Pinney, D., Candia, C., Solomon, F., … Ramesh, V. (1998). NHE-RF, a regulatory cofactor for Na+ -H+ exchange, is a common interactor for merlin and ERM (MERM) proteins. Journal of Biological Chemistry, 273(3), 1273–1276. https://doi.org/10.1074/jbc.273.3.1273
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