title: pH-Dependent channel activity of heterologously-expressed main intrinsic protein (MIP) from rat lens.
abstract: Wild-type rat lens main intrinsic protein (MIP) was heterologously expressed in the membrane of Spodoptera frugiperda (Sf21) cells using the baculovirus expression system and in mouse erythroid leukaemia cells (MEL C88). Both MEL and Sf21 cell lines expressing wild-type MIP were investigated for the conductance of ions using a whole cell patch clamp technique. An increase in conductance was seen in both expression systems, particularly on lowering the pH to 6.3. In Sf21 cells, addition of antibodies to the NPA1 box resulted in a reduction of current flow. These results suggest that MIP has pH-dependent ion channel activity, which involves the NPA1 box domain.
authors.affiliation: Division of Cell and Molecular Biology, School of Animal and Microbial Sciences, The University of Reading, P.O. Box 228, Whiteknights, Berkshire RG6 6AJ, Reading, UK.
authors.forename: K Dawn
authors.initials: KD
authors.lastname: Drake
authors.forename: Diana
authors.initials: D
authors.lastname: Schuette
authors.forename: Ana B
authors.initials: AB
authors.lastname: Chepelinsky
authors.forename: Tim J C
authors.initials: TJ
authors.lastname: Jacob
authors.forename: M James C
authors.initials: MJ
authors.lastname: Crabbe
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Jacob
mesh_terms: D000818:Animals; D020346:Aquaporins; D004553:Electric Conductivity; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D017434:Protein Structure, Tertiary; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D020346:Aquaporins; D005136:Eye Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; C030328:aquaporin 0