Syntrophin-dependent expression and localization of Aquaporin-4 water channel protein.

ABSTRACT: The Aquaporin-4 (AQP4) water channel contributes to brain water homeostasis in perivascular astrocyte endfeet where it is concentrated. We postulated that AQP4 is tethered at this site by binding of the AQP4 C terminus to the PSD95-Discs large-ZO1 (PDZ) domain of syntrophin, a component of the dystrophin protein complex. Chemical cross-linking and coimmunoprecipitations from brain demonstrated AQP4 in association with the complex, including dystrophin, beta-dystroglycan, and syntrophin. AQP4 expression was studied in brain and skeletal muscle of mice lacking alpha-syntrophin (alpha-Syn(-/-)). The total level of AQP4 expression appears normal in brains of alpha-Syn(-/-) mice, but the polarized subcellular localization is reversed. High-resolution immunogold analyses revealed that AQP4 expre

SUBMITTER: Neely JD 

PROVIDER: S-EPMC61176 | biostudies-literature | 2001 Nov

REPOSITORIES: biostudies-literature