Biology subjects

Elkayam, E.

Publications and source records attributed to Elkayam, E..

4 recordsLinked to original sources

bioRxiv2025

NOVEL SMALL-MOLECULE INHIBITORS OF THE PROTEIN KINASE DYRK: POTENTIAL THERAPEUTIC CANDIDATES IN CANCER

Dual-specificity tyrosine-regulated kinase 1A (DYRK1A) is crucial for normal brain development and its disruption has been linked to various cancers. DYRK1A drives glioblastoma (GBM) progression via stabilization of epidermal growth factor receptor (EGFR). Here we describe two, selective, benzothiazole-derived DYRK inhibitors, FC-2 and FC-3, obtained by structure-activity optimization of a natural product lead. Both compounds inhibit DYRK1A with nanomolar potency and display high selectivity across a kinase panel. The co-crystal structure of FC-3 with DYRK1A revealed ATP-competitive binding, with interactions at the hinge region and the DYRK-specific phenylalanine gatekeeper residue explaining target selectivity. Generation of inhibitor-resistant mutants confirmed DYRK1A as the primary cellular target. In GBM cell-models, FC-2 and FC-3 impaired neurosphere self-renewal, cell invasion, and EGFR stability, phenocopying DYRK1A loss. Both compounds crossed the blood-brain barrier and suppressed tumor growth, to prolong survival in intracranial xenografts. These findings identify FC-2 and FC-3 as selective small-molecule inhibitors of DYRK1A with potential therapeutic utility in GBM.

cancer biology↗

bioRxiv2025

Identification and Validation of an inhibitor of the protein kinases PIM and DYRK

Fermented wheat germ extract (FWGE), a nutraceutical with reported anticancer properties, contains numerous biologically active molecules, but its precise therapeutic constituents remain unclear. In this study, we identify and characterize a novel small-molecule inhibitor, CSH-4044, isolated from FWGE. Through preparative HPLC and structural elucidation via X-ray crystallography, CSH-4044 was revealed to be a unique benzothiazole compound. Kinase profiling demonstrated its high specificity toward the PIM and DYRK families of protein kinases. We determined the co-crystal structure of CSH-4044 bound to PIM1, revealing ATP-competitive binding, and critical hydrophobic and hydrogen-bonding interactions. A chemically synthesized version of CSH-4044 mirrored the activity of the natural product, confirming structural integrity and biological equivalence. Functionally, CSH-4044 suppressed PIM3-driven BAD phosphorylation in pancreatic cancer cells and reduced DYRK1A-mediated Tau phosphorylation in neuronal cells. Our findings position CSH-4044 as a promising lead for targeting PIM and DYRK families of kinases and highlight FWGE as a source of potential therapeutic compounds.

biochemistry↗

bioRxiv2024

The molecular basis of Human FN3K mediated phosphorylation of glycated substrate

Glycation, a non-enzymatic post-translational modification occurring on proteins, can be actively reversed via site-specific phosphorylation of the fructose-lysine moiety by FN3K kinase, to impact the cellular function of target protein. A regulatory axis between FN3K and glycated protein targets has been associated with conditions like diabetes and cancer. However the molecular basis of this relationship has not been explored so far. Here, we determined a series of crystal structures of HsFN3K in apo-state, and in complex with different nucleotide analogs together with a sugar substrate mimic to reveal the features important for its kinase activity and substrate recognition. Additionally, the dynamics in sugar substrate binding during the kinase catalytic cycle provide important mechanistic insights into HsFN3K function. Our structural work provides the molecular basis for rationale small molecule design targeting FN3K.

biochemistry↗

bioRxiv2022

Target binding triggers hierarchical phosphorylation of human Argonaute-2 to promote target release

Argonaute (Ago) proteins play a central role in post-transcriptional gene regulation through RNA interference (RNAi). Agos bind small RNAs (sRNAs) including small interfering RNAs (siRNAs) and microRNAs (miRNAs) to form the functional core of the RNA Induced Silencing Complex (RISC). The sRNA is used as a guide to target mRNAs containing either partially or fully complementary sequences, ultimately leading to down regulation of the corresponding proteins. It was previously shown that the kinase CK1 phosphorylates a cluster of residues in the eukaryotic insertion (EI) of Ago, leading to the alleviation of miRNA-mediated repression through an undetermined mechanism. We show that binding of miRNA-loaded human Ago2 to target RNA with complementarity to the seed and 3 supplemental regions of the miRNA primes the EI for hierarchical phosphorylation by CK1. The added negative charges electrostatically promote target release, freeing Ago to seek out additional targets once it is dephosphorylated. The high conservation of potential phosphosites in the EI suggests that such a regulatory strategy may be a shared mechanism for regulating miRNA-mediated repression.

biochemistry↗