Biology subjects

Brodsky, S.

Publications and source records attributed to Brodsky, S..

6 recordsLinked to original sources

bioRxiv2026

Leveraging AI and structural proteomics for rational design of a KAT6A degrader

While targeted protein degraders such as PROTACs are a clinically proven therapeutic strategy, the discovery of novel degraders remains hampered by trial-and-error process. To address this challenge, we developed the AIMS platform, which combines structural proteomics with AI models for rational PROTAC design. AIMS is an end-to-end toolkit for PROTAC optimization, encompassing structure solving using proteomics and AI, prediction of ADME and degradation properties, and prospective ranking of compound design ideas. Altogether, this integrated platform successfully enabled the multi-parameter optimization of a potent and bioavailable in vivo validated KAT6A degrader, establishing a versatile framework for PROTAC development across various targets. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=71 SRC="FIGDIR/small/727609v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@13596d0org.highwire.dtl.DTLVardef@140500eorg.highwire.dtl.DTLVardef@147e585org.highwire.dtl.DTLVardef@12dbdfe_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2025

Protein massively parallel binding assay reveals transcription factor binding determinants

Transcription factors select their genomic binding sites in genomes depending on their DNA binding domain (DBD) but also on regions outside the DBD (nonDBD). However, it remains challenging to define these determinants within nonDBDs and reveal their mechanism of action. Towards this, we introduce here an in-vivo method for parallel analysis of thousands of designed peptides for binding a DNA sequence of interest (Protein Massively Parallel Binding Assay, pMPBA). We apply it to scan the full sequence space of budding yeast TFs and generate a detailed map of DNA localizing determinants. Within the set of predicted DBDs, we reveal a large variation in DNA binding affinities, depending on the family and on different sequence characteristics, including charge. Strong signals were not confined to predicted DBDs but included a considerable fraction of nonDBD peptides, most of which were predicted as intrinsically disordered. pMPBA opens new possibilities for high-throughput analysis of peptide-DNA binding within cells.

genomics↗

bioRxiv2024

Massively Parallel Binding Assay (MPBA) reveals limited transcription factor binding cooperativity, challenging models of specificity

DNA binding domains (DBDs) within transcription factors (TFs) recognize short sequence motifs that are highly abundant in genomes. In vivo, TFs bind only a small subset of motif occurrences, which is often attributed to the cooperative binding of interacting TFs at proximal motifs. However, large-scale testing of this model is still lacking. Here, we describe a novel method allowing parallel measurement of TF binding to thousands of designed sequences within yeast cells and apply it to quantify the binding of dozens of TFs to libraries of regulatory regions containing clusters of binding motifs, systematically mutating all motif combinations. With few exceptions, TF occupancies were well explained by independent binding to individual motifs, with motif cooperation being of only limited effects. Our results challenge the general role of motif combinatorics in directing TF genomic binding and open new avenues for exploring the basis of protein-DNA interactions within cells.

systems biology↗

bioRxiv2020

Phosphorylation of Serine114 of the transcription factor ABSCISIC ACID INSENSITIVE 4 is essential for activity

The transcription factor ABA-INSENSITIVE(ABI)4 has diverse roles in regulating plant growth, including inhibiting germination and reserve mobilization in response to ABA and high salinity, inhibiting seedling growth in response to high sugars, inhibiting lateral root growth, and repressing light-induced gene expression. ABI4 activity is regulated at multiple levels, including gene expression, protein stability, and activation by phosphorylation. Although ABI4 can be phosphorylated at multiple residues by MAPKs, we found that S114 is the preferred site of MPK3. To examine the possible biological role of S114 phosphorylation, we transformed abi4-1 mutant plants with ABI4pro::ABI4 constructs encoding wild type (114S), phosphorylation-null (S114A) or phosphomimetic (S114E) forms of ABI4. Phosphorylation of S114 is necessary for the response to ABA, glucose, salt stress, and lateral root development, where the abi4 phenotype could be complemented by expressing ABI4(114S) or ABI4(S114E) but not ABI4(S114A). Comparison of root transcriptomes in ABA-treated roots of abi4-1 mutant plants transformed with constructs encoding the different phosphorylation-forms of S114 of ABI4 revealed that 85% of the ABI4-regulated genes whose expression pattern could be restored by expressing ABI4(114S) are down-regulated by ABI4. Over half of the ABI4-modulated genes were independent of the phosphorylation state of ABI4; these are enriched for stress responses. Phosphorylation of S114 was required for regulation of 35% of repressed genes, but only 17% of induced genes. The genes whose repression requires the phosphorylation of S114 are mainly involved in embryo and seedling development, growth and differentiation, and regulation of gene expression. HighlightsO_LITranscription factor ABI4 is a substrate of MAP kinases. C_LIO_LIMPK3 preferentially phosphorylates Serine 114 of ABI4. C_LIO_LIPhosphorylated Serine 114 of ABI4 is required for the complementation of abi4 mutants. C_LIO_LIPhosphorylated ABI4 acts primarily as a repressor. C_LI

plant biology↗

bioRxiv2019

Transcription-factor binding to replicated DNA

Genome replication perturbs the DNA regulatory environment by displacing DNA-bound proteins, replacing nucleosomes, and introducing dosage-imbalance between regions replicating at different S phase stages. Recently, we showed that these effects are integrated to maintain transcription homeostasis: replicated genes increase in dosage, but their expression remains stable due to replication-dependent epigenetic changes that suppress transcription. Here, we examined whether reduced transcription from replicated DNA results from limited accessibility to regulatory factors, by measuring the time-resolved binding of RNA polymerase II (RNAPII) and specific transcription factors (TFs) to DNA during S phase in budding yeast. We show that RNAPII binding-pattern is largely insensitive to DNA dosage, indicating limited binding to replicated DNA. By contrast, binding of three TFs (Reb1, Abf1 and Rap1) to DNA increased with the increasing DNA dosage. We conclude that the replication-specific chromatin environment remains accessible to regulatory factors, but suppresses RNA polymerase recruitment.

systems biology↗

bioRxiv2019

Resolving noise-control conflict by gene duplication

Gene duplication promotes adaptive evolution in two principle ways: allowing one duplicate to evolve a new function and resolving adaptive conflicts by splitting ancestral functions between the duplicates. In an apparent departure from both scenarios, low-expressing transcription factor (TF) duplicates commonly regulate similar sets of genes and act in overlapping conditions. To examine for possible benefits of such apparently redundant duplicates, we examined the budding yeast duplicated stress regulators Msn2 and Msn4. We show that Msn2,4 indeed function as one unit, inducing the same set of target genes in overlapping conditions, yet this two-factor composition allows its expression to be both environmental-responsive and with low-noise, thereby resolving an adaptive conflict that inherently limits expression of single genes. Our study exemplified a new model for evolution by gene duplication whereby duplicates provide adaptive benefit through cooperation, rather than functional divergence: attaining two-factor dynamics with beneficial properties that cannot be achieved by a single gene.

evolutionary biology↗