Hepatocytes of the periportal and perivenous zones of the liver lobule show marked differences in the contents and activities of many enzymes and other proteins. Previous studies from our and other groups have pointed towards an important role of b-catenin-dependent signaling in the regula-tion of expression of genes encoding proteins with preferential perivenous localization, whereas, in contrast, signaling through Ras-dependent path-way(s) may induce a ‘periportal’ phenotype.
