Biology subjects

Khan, K. S.

Publications and source records attributed to Khan, K. S..

3 recordsLinked to original sources

bioRxiv2026

Rewiring c-Myc Transcriptional Activity with an O-GlcNAcylation Targeting Chimera (OGTAC)

c-Myc is a transcription factor that drives tumorigenesis in many cancers. It is notoriously difficult to directly target c-Myc, mainly due to its lack of well-defined druggable pockets. O-linked {beta}-N-acetylglucosamine modification (O-GlcNAcylation) is a post-translational modification (PTM) playing an important role in regulating c-Myc functions in cancer. However, previous studies have primarily relied on global perturbations to investigate c-Myc O-GlcNAcylation, making it difficult to determine its direct functional consequences due to concurrent cellular effects. Here, we report a bifunctional O-GlcNAcylation TArgeting Chimera (OGTAC) molecule, which can induce the proximity of c-Myc and O-GlcNAc transferase (OGT) in living cells, thereby enhancing the O-GlcNAcylation of c-Myc. The c-Myc-targeting OGTAC exhibits anti-proliferation effect against cancer cells. Mapping of c-Myc occupancy on genome indicates that OGTAC rewires c-Myc transcriptional activity and reprograms expression of the downstream oncogene MALAT1, in an O-GlcNAcylation-dependent manner. Overall, OGTAC presents a novel chemically induced proximity (CIP)-based tool to target and rewire c-Myc activity in cancer. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=135 SRC="FIGDIR/small/722559v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@d1c640org.highwire.dtl.DTLVardef@2eb70corg.highwire.dtl.DTLVardef@f38970org.highwire.dtl.DTLVardef@c421c8_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2023

Targeted Protein O-GlcNAcylation Using Bifunctional Small Molecules

Protein O-linked {beta}-N-acetylglucosamine modification (O-GlcNAcylation) plays a crucial role in regulating essential cellular processes. The disruption of O-GlcNAcylation homeostasis has been linked to various human diseases, including cancer, diabetes, and neurodegeneration. However, there are limited chemical tools for protein- and site-specific O-GlcNAc modification, rendering the precise study of O-GlcNAcylation challenging. To address this, we have developed first-in-class heterobifunctional small molecules, named O-GlcNAcylation targeting chimeras (OGTACs), which enable protein-specific O-GlcNAcylation in cells. OGTACs promote O-GlcNAcylation of proteins such as BRD4, CK2, and EZH2 in cellulo by recruiting O-GlcNAc transferase (OGT), with temporal and magnitude control. Mass spectrometry data revealed that OGTACs induced site-selective O-GlcNAcylation of BRD4. Overall, OGTACs represent a promising approach for inducing protein-specific O-GlcNAcylation, thus enabling functional dissection and offering new directions for O-GlcNAc-targeting therapeutic development.

cell biology↗

bioRxiv2020

Simeprevir suppresses SARS-CoV-2 replication and synergizes with remdesivir

The outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global threat to human health. Using a multidisciplinary approach, we identified and validated the hepatitis C virus (HCV) protease inhibitor simeprevir as an especially promising repurposable drug for treating COVID-19. Simeprevir potently reduces SARS-CoV-2 viral load by multiple orders of magnitude and synergizes with remdesivir in vitro. Mechanistically, we showed that simeprevir inhibits the main protease (Mpro) and unexpectedly the RNA-dependent RNA polymerase (RdRp). Our results thus reveal the viral protein targets of simeprevir, and provide preclinical rationale for the combination of simeprevir and remdesivir for the pharmacological management of COVID-19 patients. One Sentence SummaryDiscovery of simeprevir as a potent suppressor of SARS-CoV-2 viral replication that synergizes with remdesivir.

microbiology↗