CAAXmotiivins

CAAXmotiivins refers to a conserved motif found in prenylated proteins. The CAAX box is a C-terminal amino acid sequence that consists of a cysteine residue, followed by an aliphatic amino acid (A), and then two variable amino acids (XX). This motif serves as a signal for the post-translational modification of farnesylation or geranylgeranylation, a process commonly known as prenylation. Enzymes called prenyltransferases recognize the CAAX box and attach an isoprenoid lipid chain to the cysteine residue. This lipid modification is crucial for the proper localization, function, and protein-protein interactions of many cellular proteins. Proteins containing the CAAX motif are involved in a variety of cellular processes, including signal transduction, cell cycle regulation, and membrane trafficking. Examples of proteins that undergo CAAX prenylation include Ras GTPases, lamins, and some protein kinases. The specific identity of the last two amino acids in the XX position can influence which prenyltransferase acts on the protein and the type of lipid added. This detail can have significant consequences for the protein's final destination and biological activity. Understanding the CAAX motif and its associated prenylation is important for comprehending cellular signaling pathways and developing therapeutic strategies targeting prenylated proteins.