Lipid modifications of proteins - slipping in and out of membranes

Protein lipid modification, once thought to act as a stable membrane anchor for soluble proteins, is now attracting more widespread attention for its emerging role in diverse signaling pathways and regulatory mechanisms. Most multicellular organisms have recruited specific types of lipids and a suit e of unique enzymes to catatyze the modification of a select number of prot eins, many of which are evolutionarily conserved in plants, animals and fun gi. Each of the three known types of lipid modification - palmitoylation, m yristylation and prenylation - allows cells to target proteins to the plasm a membrane, as well as to other subcellular compartments. Among the lipid m odifications, protein prenylation might also function as a relay between cy toplasmic isoprene biosynthesis and regulatory pathways that control cell c ycle and growth, Molecular and genetic studies of an Arabidopsis mutant tha t tacks farnesyl transferase suggest that the enzyme has a role in abscisic acid signaling during seed germination and in the stomata. it is becoming clear that lipid modifications are not just fat for the protein, but part o f a highly conserved intricate network that plays a role in coordinating co mplex cellular functions.