Post-translational modification (PTM) is the chemical modification of a protein after its creation (translation). This modification can affect protein behavior such as gene expression. Post-translational modifications include phosphorylation, glycosylation, acetylation, methylation, ubiquitylation, and sulfation. After protein synthesis, PTM increases the range of protein function by attaching it to other proteins or to other functional groups like acetate, phosphate, various lipids, and carbohydrates. PTMs regulate cellular activity and occur at distinct amino acid side chains or peptide linkages. They are most often mediated by enzymatic activity and can be reversible depending on the nature of the modification.
Sigma provides several compounds to study the pivotal role of PTMs in normal cell biology and diseases where multiple genes are involved, such as heart disease, cancer, neurodegenerative diseases, and diabetes.
p21ras farnesyltransferase inhibitor. While many tetrapeptide "inhibitors" of p21ras FTase are known, most act instead as competitive substrates. This compound is not farnesylated and is thus a true inhibitor.1
FTI-276 is a highly potent RasCAAX peptidomimetic. FTI-276 antagonizes both H and K-Ras oncogenic signaling. It is an inhibitor of farnesyltransferase (Ftase) in vitro with an IC50 of 500 pM and is an anti-cancer agent.
Golgicide A is a potent, highly specific, reversible inhibitor of the cis-Golgi ArfGEF GBF1. Arf proteins are members of the Ras superfamily of small guanosine triphosphatases (GTPases) that mediate vesicular transport. Golgicide A binds within an interfacial cleft formed between Arf1 and the GBF1 Sec7 domain. Golgicide A is a unique and powerful tool for further elucidating the mechanisms underlying assembly and transport within the Golgi, comparable to the use of dynasore for studying the dynamics of dynamin-mediated clathrin coat formation.
Hydroxy-Dynasore is a cell permeable and potent dynamin inhibitor that prevents uptake of recombinant botulinum neurotoxin A heavy chain binding domain (BoNT/A-Hc). Apparently, Hydroxy-Dynasore prevents dynamin-mediated fission of endocytic vesicles from the plasma membrane.
ITX3 is a specific inhibitor of endogenous TrioN activity acting on the GEF domain and selective cell active inhibitor of the Trio/RhoG/Rac1 pathway. The compound is active in whole cell assay where it inhibits the formation of TrioN-dependent cell structures. ITX3 appears to be specific for TrioN inhibition rather than other RhoGEFs.
Long chain fatty acid (C16) covalently linked to Coenzyme A. Covalent attachment of palmitate is a common occurrence on a wide variety of viral and cellular proteins and plays a role in promoting membrane binding. Palmitoylation may also be a general mechanism for prolonging or potentiating G-protein signaling.