Biology subjects

Amrhein, J. A.

Publications and source records attributed to Amrhein, J. A..

3 recordsLinked to original sources

bioRxiv2025

Un-LOK-ing a new approach for conformational selective targeting of STK10 (LOK)

STK10 (serine/threonine kinase 10, LOK), is an important regulator of diverse cellular processes, such as cell cycle progression or lymphocyte migration. STK10 has emerged as a potential therapeutic target for diseases associated with impaired cell migration and cell division. Here we present a late-stage optimization of a macrocyclic pyrazolo[1,5-a]pyrimidine scaffold that led to a urea-based lead series targeting the back-pocket of STK10. Co-crystal structure analysis of 23 revealed that the optimized macrocycles adopted a unique binding mode that protrudes deep into the back pocket of STK10. Compound 23 exhibited potent on-target activity in biophysical and activity assays and displayed nanomolar activity for STK10 in cells. In addition, 23 shows good selectivity against the kinome and remarkably also against the closely related kinase SLK (STE20-like kinase). Therefore, we propose that targeting the unique and largely extended pocket in STK10 represents an opportunity to develop highly selective STK10 inhibitors. TOC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=85 SRC="FIGDIR/small/666149v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@36f039org.highwire.dtl.DTLVardef@d55025org.highwire.dtl.DTLVardef@80c007org.highwire.dtl.DTLVardef@bf2471_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2025

Development of pyrazolopyrimidine based macrocyclic kinase inhibitors targeting AAK1

Since the outbreak of SARS-CoV-2 in recent years, our society has become more aware that zoonotic diseases pose a real threat. Therefore, the demand for small molecules that target host proteins, essential for viral entry and replication, has increased as an interesting strategy for the development of antiviral agents, as these agents may be effective against several different pathogens. NAK kinases is one such potential target family because they are involved in a variety of cellular functions, hijacked by viruses to invade host cells, such as clathrin-mediated endocytosis. A large number of different inhibitors have already been reported targeting NAK kinases, but there are still no compounds that selectively target AAK1 over other NAK family members, in particular the closely related family member BIKE. Here, we developed a series of pyrazolo[1,5-a]pyrimidine-based macrocyclic NAK inhibitors, starting from the acyclic AAK1 inhibitor LP-935509. Through a structure-guided activity relationship study within the NAK family, we identified potent AAK1 inhibitors 16, 18 and 27, which show promising selectivity within the NAK family. The inhibitors showed a potent inhibition of the phosphorylation of the AP-2 complex and the antiviral activity of the compounds was evaluated against various RNA viruses.

biochemistry↗

bioRxiv2023

Synthesis of pyrazole-based macrocycles leads to a highly selective inhibitor for MST3

MST1, MST2, MST3, MST4, and YSK1 are conserved members of the mammalian sterile 20 kinase (MST) family. MSTs regulate key cellular functions such as cell proliferation, cell migration, metabolic regulation, and cell polarity. The MST3 isozyme plays a role in regulation of cell growth, autophagy and apoptosis, and its dysregulation has been linked to the occurrence of high-grade tumors with poor survival prognosis. To date, there are no isoform-selective inhibitors available that could be used for validating the role of MST3 in tumorigenesis and to assess its potential as an anti-cancer target for drug development. To this end, we have designed a new series of 3-aminopyrazole-based macrocycles based on the structure of an acyclic promiscuous kinase inhibitor. By varying moieties targeting the solvent-exposed region and optimizing the linker, macrocycle JA310 (21c) was synthesized. JA310 exhibited high cellular potency for MST3 with an EC50 = 106 nM and excellent kinome-wide selectivity with significantly lower cellular activity on the closely related kinase MST4 (EC50 = 1.4 {micro}M). The high-resolution crystal structure of the MST3-JA310 complex provided intriguing insights into the distinct binding mode of the macrocycle, which was associated with large-scale structural rearrangements, including concerted induced-fit movements of the glycine-rich loop, the C helix, and the activation loop. In summary, the developed macrocyclic MST3 inhibitor, JA310, demonstrates the utility of macrocyclization for the design of highly selective inhibitors and presents a first chemical probe for MST3.

biochemistry↗