METABOLIC COMPARTMENTATION IN LIVING CELLS - STRUCTURAL ASSOCIATION OF ALDOLASE

The glycolytic enzyme aldolase is concentrated in a domain around stre ss fibers in living Swiss 3T3 cells, but the mechanism by which aldola se is localized has not been revealed. We have recently identified a m olecular binding site for F-actin on aldolase, and we hypothesized tha t this specific binding interaction, rather than a nonspecific mechani sm, is responsible for localizing aldolase in vivo. In this report, we have used fluorescent analog cytochemistry of a site-directed mutant of aldolase to demonstrate that actin-binding activity localizes this molecule along stress fibers in quiescent cells and behind active ruff les in the leading edge of motile cells. The specific cytoskeletal ass ociation of aldolase could play a structural role in cytoplasm, and it may contribute to metabolic regulation, metabolic compartmentation, a nd/or cell motility. Functional duality may be a widespread feature am ong cytosolic enzymes. (C) 1997 Academic Press.