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Serine hydroxymethyltransferase 2 (SHMT2) regulates one-carbon transfer reactions that are essential for amino acid and nucleotide metabolism, and uses pyridoxal-5′-phosphate (PLP) as a cofactor. Apo SHMT2 exists as a dimer with unknown functions, whereas PLP binding stabilizes the active tetrameric state. SHMT2 also promotes inflammatory cytokine signalling by interacting with the deubiquitylating BRCC36 isopeptidase complex (BRISC), although it is unclear whether this function relates to metabolism. Here we present the cryo-electron microscopy structure of the human BRISC–SHMT2 complex at a resolution of 3.8 Å. BRISC is a U-shaped dimer of four subunits, and SHMT2 sterically blocks the BRCC36 active site and inhibits deubiquitylase activity. Only the inactive SHMT2 dimer—and not the active PLP-bound tetramer—binds and inhibits BRISC. Mutations in BRISC that disrupt SHMT2 binding impair type I interferon signalling in response to inflammatory stimuli. Intracellular levels of PLP regulate the interaction between BRISC and SHMT2, as well as inflammatory cytokine responses. These data reveal a mechanism in which metabolites regulate deubiquitylase activity and inflammatory signalling.

We developed a scalable synthesis of γ-thiolysine starting straight from lysine. The application of γ-thiolysine was compared to δ-thiolysine in the chemical synthesis of K48 and K33 linked diubiquitin conjugates. Both γ- and δ-thiolysine were found to perform equally efficiently as handles for non-enzymatic ubiquitination.

De enzymen protein:farnesyl transferase (PFT) en protein:geranylgeranyl transferase-1 (PGGT-1) zijn verantwoordelijk voor de post-translationele modificatie van kleine G-eiwitten noodzakelijk voor hun binding aan celmembranen. Sinds het begin van de jaren __80 is bekend dat het remmen van PFT voorkomt dat bepaalde gemuteerde G-eiwitten die kanker veroorzaken volwassen worden. Naast anti-kanker therapie_n, zijn er de laatste jaren steeds meer duidelijke aanwijzingen dat PFT en PGGT-1 remmers voor andere therapeutische toepassingen gebruikt kunnen. Hierbij gaat het om bestrijding van osteoporose (botontkalking), atherosclerose en restenose (aderverkalking), angiogenese (de vorming van nieuwe bloedvaten), malaria en multiple sclerose. Mogelijk zal dit jaar de PFT remmer Tipifarnib__ (Johnson & Johnson) goedgekeurd worden voor de behandeling van Acute Myelo_de Leukemie. Het proefschrift beschrijft enkele synthetische methoden voor het ontwikkelen van potente PFT en PGGT-1 remmers (in samenwerking met Gaubius Laboratorium, TNO Quality of Life). Zo is voor PFT een potente en selectieve PFT remmer ontwikkeld waarvan de werking in cellen ook is aangetoond. Naast de bio-organische synthetische methoden, is een __proteomics__ (onderzoek naar eiwitten en hun functie in de cel) methode ontwikkeld dat het mogelijk moet maken om tot nu toe onbekende PFT en PGGT-1 substraten te isoleren en identificeren.|The prenyl transferases protein:farnesyl transferase (PFT) and protein:geranylgeranyl transferase-1 (PGGT-1) are responsible for the post-translational modification of small Gproteins. This post-translational modification comprises the attachment of an isoprenoid (farnesyl or gerangeranyl) to the C-terminus of the G-protein and is essential for a proper cellular membrane localization and function. Since the beginning of the 80__s it is known that inhibition of PFT prevents the maturation of certain mutated (small) G-proteins involved in tumorogenesis. Besides anti-cancer therapies, it is becoming more and more obvious that PFT and/or PGGT-1 inhibitors also hold promise for the treatment of osteoporosis (bone resorption), atherosclerosis and restenosis (thickening of the inner lining of an artery), angiogenesis (formation of new bloodvessels), malaria and multiple sclerosis. At the moment the PFT inhibitor Tipifarnib_ (Johnson & Johnson) has been submitted for approval by the FDA for the treatment of Acute Myeloid Leukemia (AML). The Thesis by Farid El Oualid presents several synthethic approaches toward the development of potent PFT and/or PGGT-1 inhibitors (in cooperation with the Gaubius Laboratory, TNO Quality of Life). For PFT a potent and very selective inhibitor was found. Besides being active against pure PFT, the inhibitor was also shown to be active in cultured cells. In addition to the bio-organic synthethic methods, a __proteomics__ strategy was developed which should make it possible to isolate and identify unknown PFT (and PGGT-1) substrates