Biology subjects

Madsen, A. S.

Publications and source records attributed to Madsen, A. S..

3 recordsLinked to original sources

bioRxiv2020

Selective inhibitors of SIRT2 regulate perinuclear α-tubulin acetylation, migration, and invasion of breast cancer cells

Sirtuin 2 (SIRT2) is a protein deacylase enzyme that removes acetyl groups and longer chain acyl groups from post-translationally modified lysine residues. It affects diverse biological functions in the cell and has been considered a drug target in relation to both neurodegenerative diseases and cancer. Therefore, access to well-characterized and robust tool compounds is essential for the continued investigation of the complex functions of this enzyme. Here, we report a collection of probes that are potent, selective, stable in serum, water-soluble, amenable to cell culture experiments, and inhibit both SIRT2 deacetylation and demyristoylation. Compared to the current landscape of SIRT2 inhibitors, this is a unique ensemble of features built into a single compound. We expect the developed chemotypes to find broad application in the interrogation of SIRT2 functions in both healthy and diseased cells, and to provide a foundation for the development of future therapeutics.

biochemistry↗

bioRxiv2018

An NAD+-dependent sirtuin depropionylase and deacetylase (Sir2La) from the probiotic bacterium Lactobacillus acidophilus NCFM

Sirtuins--a group of NAD+-dependent deacylases--have emerged as key in the connection between NAD+ metabolism and aging. This class of enzymes hydrolyze a range of{varepsilon} -N-acyllysine PTMs and determining the repertoire of catalyzed deacylation reactions is of high importance to fully elucidate the roles of a given sirtuin. Here we have identified and produced two potential sirtuins from the probiotic bacterium Lactobacillus acidophilus NCFM and screening more than 80 different substrates, covering 26 acyl groups on five peptide scaffolds, showed that one of the investigated proteins--Sir2La--is a bona fide NAD+-dependent sirtuin, catalyzing hydrolysis of acetyl-, propionyl-, and butyryllysine. Further substantiating the identity as a sirtuin, known sirtuin inhibitors nicotinamide and suramin as well as a thioacetyllysine compound inhibit the deacylase activity in a concentration-dependent manner. Based on steady-state kinetics Sir2La showed a slight preference for propionyllysine over acetyllysine and butyryllysine, driven both by KM (14 M vs 21 M and 15 M) and kcat (4.4{middle dot}10-3 s-1 vs 2.5{middle dot}10-3 s-1 and 1.21{middle dot}10-3 s-1). Moreover, while NAD+ is a prerequisite for Sir2La-mediated deacylation, Sir2La has very high KM for NAD+ compared to the expected levels of the dinucleotide in L. acidophilus. Sir2La is the first sirtuin from Lactobacillales and of the Gram-positive bacterial subclass of sirtuins to be functionally characterized. The ability to hydrolyze propionyl- and butyryllysine emphasizes the relevance of further exploring the role of other short-chain acyl moieties as PTMs.

biochemistry↗

bioRxiv2017

Histone Deacetylase 11 is an ε-N-Myristoyllysine Hydrolase

Histone deacetylase (HDAC) enzymes are important regulators of diverse biological function, including gene expression, rendering them potential targets for intervention in a number of diseases, with a handful of compounds approved for treatment of certain hematologic cancers. Among the human zinc-dependent HDACs, the most recently discovered member, HDAC11, is the only member assigned to subclass IV, the smallest protein, and the least well understood with regards to biological function. Here we show that HDAC11 cleaves long chain acyl modifications on lysine side chains with remarkable efficiency compared to acetyl groups. We further show that several common types of HDAC inhibitors, including the approved drugs romidepsin and vorinostat, do not inhibit this enzymatic activity. Macrocyclic hydroxamic acid-containing peptides, on the other hand, potently inhibit HDAC11 demyristoylation activity. These findings should be taken carefully into consideration in future investigations of the biological function of HDAC11 and will serve as a foundation for the development of selective chemical probes targeting HDAC11.

biochemistry↗