IDENTIFICATION OF 4 DISTINCT POOLS OF CATENINS IN MAMMALIAN-CELLS ANDTRANSFORMATION-DEPENDENT CHANGES IN CATENIN DISTRIBUTIONS AMONG THESEPOOLS

Catenins are cytoplasmic proteins that were initially identified in a complex with cadherins, a superfamily of transmembrane glycoproteins i mportant for cell adhesion in normal and disease states, We have used gel filtration to identify four complexes of catenins in extracts from normal and transformed epithelial cells, In normal Madin-Darby canine kidney epithelial cells, a significant fraction of alpha- and beta-ca tenin and plakoglobin co-elute with cadherin in a high molecular weigh t complex (complex I), A portion of alpha-catenin and the remainder of beta-catenin and plakoglobin co-elute in a high molecular weight comp lex that does not contain cadherin (complex II). The remainder of alph a-catenin elutes in a low molecular weight fraction (complex III). In extracts from two colon carcinoma cell lines, HCT116 and SW480, beta-c atenin elutes in an additional low molecular weight pool (complex IV) not present in Madin-Darby canine kidney cell extracts, In two subclon es derived from SW480 cells, SW-E8 and SW-R2, beta-catenin is distribu ted evenly between high and low molecular weight pools in SW-ES cells, whereas it elutes primarily in the low molecular weight pool (complex TV) in SW-RB cells, These changes in beta-catenin elution profiles co rrelate with an increase in transformed phenotype and decreased cell-c ell adhesion in the SW-RP cells.