CBP35-CBP67 INTERACTION DURING STRESS-RES PONSE AND AGING

Three carbohydrate-binding proteins with relative molecular masses of 35,67, and 70 kDa (CBP35, CBP67, and CBP70) have been described to be present in nuclei of mammalian cells, where they are associated with n uclear ribonucleoprotein (RNP) complexes. CBP35 consists of two domain s, an N-terminal domain that is homologous to certain regions of prote ins of the heterogeneous nuclear RNP complex, and a C-terminal domain that is homologous to beta-galactoside-specific lectins. CBP35 has bee n proposed, like the glucose-specific lectin, CBP67, to guide RNP comp lexes through the nuclear pore. Here, we show that exposition of matur e rats (6-8 months old) to stress results in binding of nuclear CBP35 to CBP67 which is retained on a column containing immobilized glucose. In contrast to mature animals, nuclear extracts from the livers of ol d rats (22-24 months old) displayed no detectable stress response.