REGIONAL DIFFERENCES IN THE POLYPEPTIDE COMPOSITION OF PIG LENS INTRACELLULAR MATRIX AND PLASMA-MEMBRANE

Analysis of pig lens urea-soluble fractions (USF) by get filtration an d SDS-PAGE revealed that the cortical USF is characterized by a high c ontent of noncrystallin bands of 42, 44, 52, 55, 100 and 200 kD. These bands are markedly decreased in the nuclear USF though the 44-kD band to a lesser extent. These results suggested that pig lens nucleus con tains much less cytoskeletal proteins than the cortex. Analysis of pig lens membrane showed that MP26 and MP17 are the major intrinsic membr ane proteins and the relative amount of alphaA and betaB1b chains atta ched to the membrane are more abundant in the nucleus than in the cort ex.