Palmitoylation

Not to be confused with Palmitoleoylation.
In palmitoylation, a palmitoyl group (derived from palmitic acid, pictured above) is added.
Palmitoylation of a cysteine residue
Left Palmitoylation (red) anchors Ankyrin G to the plasma membrane. Right Close up. Palmityl residue in yellow.
Palmitoylation of Gephyrin Controls Receptor Clustering and Plasticity of GABAergic Synapses[1]

In molecular biology, palmitoylation is the covalent attachment of fatty acids, such as palmitic acid, to cysteine (S-palmitoylation) and less frequently to serine and threonine (O-palmitoylation) residues of proteins, which are typically membrane proteins.[2] The precise function of palmitoylation depends on the particular protein being considered. Palmitoylation enhances the hydrophobicity of proteins and contributes to their membrane association. Palmitoylation also appears to play a significant role in subcellular trafficking of proteins between membrane compartments,[3] as well as in modulating protein–protein interactions.[4]

In contrast to prenylation and myristoylation, palmitoylation is usually reversible (because the bond between palmitic acid and protein is often a thioester bond). The reverse reaction in mammalian cells is catalyzed by acyl-protein thioesterases (APTs) in the cytosol and palmitoyl protein thioesterases in lysosomes. Because palmitoylation is a dynamic, post-translational process, it is believed to be employed by the cell to alter the subcellular localization, protein–protein interactions, or binding capacities of a protein.

An example of a protein that undergoes palmitoylation is hemagglutinin, a membrane glycoprotein used by influenza to attach to host cell receptors.[5] The palmitoylation cycles of a wide array of enzymes have been characterized in the past few years, including H-Ras, Gsα, the β2-adrenergic receptor, and endothelial nitric oxide synthase (eNOS). In signal transduction via G protein, palmitoylation of the α subunit, prenylation of the γ subunit, and myristoylation is involved in tethering the G protein to the inner surface of the plasma membrane so that the G protein can interact with its receptor.[6]

  1. ^ Cite error: The named reference bori2014 was invoked but never defined (see the help page).
  2. ^ Linder, M.E., "Reversible modification of proteins with thioester-linked fatty acids," Protein Lipidation, F. Tamanoi and D.S. Sigman, eds., pp. 215-40 (San Diego, CA: Academic Press, 2000).
  3. ^ Rocks O, Peyker A, Kahms M, Verveer PJ, Koerner C, Lumbierres M, Kuhlmann J, Waldmann H, Wittinghofer A, Bastiaens PI (2005). "An acylation cycle regulates localization and activity of palmitoylated Ras isoforms". Science. 307 (5716): 1746–1752. Bibcode:2005Sci...307.1746R. doi:10.1126/science.1105654. PMID 15705808. S2CID 12408991.
  4. ^ Basu, J., "Protein palmitoylation and dynamic modulation of protein function," Current Science, Vol. 87, No. 2, pp. 212-17 (25 July 2004), http://www.ias.ac.in/currsci/jul252004/contents.htm
  5. ^ Palese, Peter; García-Sastre, Adolfo (1999). "INFLUENZA VIRUSES (ORTHOMYXOVIRIDAE) | Molecular Biology". Encyclopedia of Virology. pp. 830–836. doi:10.1006/rwvi.1999.0157. ISBN 9780122270307. Archived from the original on 2012-09-12.
  6. ^ Wall, MA; Coleman, DE; Lee, E; Iñiguez-Lluhi, JA; Posner, BA; Gilman, AG; Sprang, SR (Dec 15, 1995). "The structure of the G protein heterotrimer Gi alpha 1 beta 1 gamma 2". Cell. 83 (6): 1047–58. doi:10.1016/0092-8674(95)90220-1. PMID 8521505.