The 14-3-3 proteins: cellular regulators of plant metabolism

Signal transduction and enzyme regulation are known to occur via phosphoryl ation, but it is becoming increasingly apparent that phosphorylation might be only a necessary preamble to regulation. In many cases, the phosphorylat ed target protein must associate with a specialized adapter protein, known as 14-3-3, to complete the regulatory action. There are several prominent e xamples of 14-3-3 participation in plant regulatory events, including the r egulation of plasma membrane H+-ATPase, nitrate reductase and sucrose phosp hate synthase, However, emerging data on 14-3-3s in the nucleus might exten d the roles for 14-3-3s well beyond the regulation of cytoplasmic enzymes.