Proteolytic changes in main intrinsic polypeptide (MIP26) from membranes in selenite cataract.
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.
David
L L
LL
Department of Biochemistry, Oregon Health Sciences University, Portland 97201.
Takemoto
L J
LJ
Anderson
R S
RS
Shearer
T R
TR
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
D020346:Aquaporins; D005136:Eye Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C030328:aquaporin 0; D010447:Peptide Hydrolases; D020887:Selenious Acid; D012643:Selenium