title: Proteolytic changes in main intrinsic polypeptide (MIP26) from membranes in selenite cataract.
abstract: Experimental nuclear cataract produced by an overdose of sodium selenite exhibited limited proteolysis, including breakdown of main intrinsic polypeptide (MIP26) to 24 and 22 kD fragments. Micro-sequencing and site specific immunologic probes were used in the present study to determine regions of cleavage in MIP26 during selenite cataractogenesis. Data suggested that proteolysis occurred in the C-terminus of MIP26. This may have lead to exposure of normally hidden amino acid residues on the C-terminal extension of MIP26. Loss of antigenicity of the N-terminus occurred. These significant changes to the MIP26 molecule might adversely affect communication between lens fiber cells and contribute to selenite cataract.
authors.affiliation: Department of Biochemistry, Oregon Health Sciences University, Portland 97201.
authors.forename: L L
authors.initials: LL
authors.lastname: David
authors.forename: L J
authors.initials: LJ
authors.lastname: Takemoto
authors.forename: R S
authors.initials: RS
authors.lastname: Anderson
authors.forename: T R
authors.initials: TR
authors.lastname: Shearer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020346:Aquaporins; D002386:Cataract / Q000139:chemically induced / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005136:Eye Proteins / Q000378:metabolism*; D007158:Immunologic Techniques; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000378:metabolism; D008566:Membranes / Q000378:metabolism; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism*; D020887:Selenious Acid; D012643:Selenium
chemical_list: D020346:Aquaporins; D005136:Eye Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C030328:aquaporin 0; D010447:Peptide Hydrolases; D020887:Selenious Acid; D012643:Selenium