On the trail of an elusive flux sensor

The hexokinase I'll isozyme has been implicated as an essential component of multiple glucose sensing pathways in the yeast Saccharomyces cerevisiae. Several lines of evidence suggest that the flux through this enzymatic step, but not the levels of substrates, cofactors or products, is the critical process detected by downstream sensing machinery. In spite of intensive research efforts, how the activity of this enzyme is translated into a quantitative signal remains an unresolved question. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.