Advancing Multiple Detection in RT-LAMP with a Specific Probe Assembled from Plural Three-Way-Junction Structures.

The timely detection of diseases and the accurate identification of pathogens require the development of efficient and reliable diagnostic methods. In this study, we have developed a novel specific multivariate probe termed MRTFP (multivariate real-time fluorescent probe) by assembling strand exchange three-way-junction (3WJ) structures. The 3WJ structures were incorporated into a four-angle probe (FP) and a hexagonal probe (HP), to target the multivariate genes of Salmonella. The FP and HP enable single-step and multiplexed detection in RT-LAMP (real-time loop-mediated isothermal amplification) with exceptional sensitivity and specificity. Encouragingly, real food samples contaminated with Salmonella (Salmonella enteritidis and Salmonella typhimurium) can be readily identified and distinguished with a minimum detectable concentration (MDC) of 103 CFU/mL without the need for further culture. The introduction of MRTFP allows for simultaneous detection of dual or three targets in a single tube for LAMP, thereby improving detection efficiency. The MRTFP simplifies the design of robust multivariate probes, exhibits excellent stability, and avoids interference from multiple probe units, offering significant potential for the development of specific probes for efficient and accurate disease detection and pathogen identification.

Characterization of a membrane binding loop leads to engineering botulinum neurotoxin B with improved therapeutic efficacy.

Botulinum neurotoxins (BoNTs) are a family of bacterial toxins with seven major serotypes (BoNT/A-G). The ability of these toxins to target and bind to motor nerve terminals is a key factor determining their potency and efficacy. Among these toxins, BoNT/B is one of the two types approved for medical and cosmetic uses. Besides binding to well-established receptors, an extended loop in the C-terminal receptor-binding domain (HC) of BoNT/B (HC/B) has been proposed to also contribute to toxin binding to neurons by interacting with lipid membranes (termed lipid-binding loop [LBL]). Analogous loops exist in the HCs of BoNT/C, D, G, and a chimeric toxin DC. However, it has been challenging to detect and characterize binding of LBLs to lipid membranes. Here, using the nanodisc system and biolayer interferometry assays, we find that HC/DC, C, and G, but not HC/B and HC/D, are capable of binding to receptor-free lipids directly, with HC/DC having the highest level of binding. Mutagenesis studies demonstrate the critical role of consecutive aromatic residues at the tip of the LBL for binding of HC/DC to lipid membranes. Taking advantage of this insight, we then create a "gain-of-function" mutant HC/B by replacing two nonaromatic residues at the tip of its LBL with tryptophan. Cocrystallization studies confirm that these two tryptophan residues do not alter the structure of HC/B or the interactions with its receptors. Such a mutated HC/B gains the ability to bind receptor-free lipid membranes and shows enhanced binding to cultured neurons. Finally, full-length BoNT/B containing two tryptophan mutations in its LBL, together with two additional mutations (E1191M/S1199Y) that increase binding to human receptors, is produced and evaluated in mice in vivo using Digit Abduction Score assays. This mutant toxin shows enhanced efficacy in paralyzing local muscles at the injection site and lower systemic diffusion, thus extending both safety range and duration of paralysis compared with the control BoNT/B. These findings establish a mechanistic understanding of LBL-lipid interactions and create a modified BoNT/B with improved therapeutic efficacy.

SARS-CoV-2 Point-of-Care (POC) Diagnosis Based on Commercial Pregnancy Test Strips and a Palm-Size Microfluidic Device.

Coronavirus diseases such as the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), pose serious threats. Portable and accurate nucleic acid detection is still an urgent need to achieve on-site virus screening and timely infection control. Herein, we have developed an on-site, semiautomatic detection system, aiming at simultaneously overcoming the shortcomings suffered by various commercially available assays, such as low accuracy, poor portability, instrument dependency, and labor intensity. Ultrasensitive isothermal amplification [i.e., reverse transcription loop-mediated isothermal amplification (RT-LAMP)] was applied to generate intensified SARS-CoV-2 RNA signals, which were then transduced to portable commercial pregnancy test strips (PTSs) via ultraspecific human chorionic gonadotropin (hCG)-conjugated toehold-mediated strand exchange (TMSE) probes (hCG-P). The entire detection was integrated into a four-channel, palm-size microfluidic device, named the microfluidic point-of-care (POC) diagnosis system based on the PTS (MPSP) detection system. It provides rapid, cost-effective, and sensitive detection, of which the lowest concentration of detection was 0.5 copy/µL of SARS-CoV-2 RNA, regardless of the presence of other similar viruses, even highly similar severe acute respiratory syndrome coronavirus (SARS-CoV). The successful detection of the authentic samples from different resources evaluated the practical application. The commercial PTS provides a colorimetric visible signal, which is instrument- and optimization-free. Therefore, this MPSP system can be immediately used for SARS-CoV-2 emergency detection, and it is worthy of further optimization to achieve full automation and detection for other infectious diseases.

Beyond botulinum neurotoxin A for chemodenervation of the bladder.

PURPOSE OF REVIEW: Botulinum neurotoxin A (BoNT/A), or Botox, is a popular option for overactive bladder (OAB) and neurogenic bladder (NGB) with or without incontinence. This review aims to discuss the clinical outcomes of BoNT in adult and pediatric bladder conditions, and introduces the potential benefit of novel, engineered neurotoxins beyond BoNT/A. RECENT FINDINGS: A large volume of evidence supports the use of Botox for OAB (to reduce urgency, frequency and incontinence episodes), and for NGB (to decrease incontinence and improve bladder capacity and detrusor pressures). Botox is now also Food & Drug Administration (FDA)-approved for pediatric neurogenic detrusor overactivity. However, urinary retention, diminished response over time and treatment failures are prevalent issues with Botox. Modifying natural BoNTs or forming chimeric toxins are alternatives to BoNT/A that may have higher efficacy and lower side-effect profile. One example is BoNT/BMY-WW. This novel engineered toxin binds to a more commonly expressed synaptotagmin receptor, with potentially more potent paralytic effect and less capacity for systemic diffusion. SUMMARY: Novel engineered neurotoxins may be the next frontier in OAB and NGB therapy.

Electrostatic Forces Mediate the Specificity of RHO GTPase-GDI Interactions.

Three decades of research have documented the spatiotemporal dynamics of RHO family GTPase membrane extraction regulated by guanine nucleotide dissociation inhibitors (GDIs), but the interplay of the kinetic mechanism and structural specificity of these interactions is as yet unresolved. To address this, we reconstituted the GDI-controlled spatial segregation of geranylgeranylated RHO protein RAC1 in vitro. Various biochemical and biophysical measurements provided unprecedented mechanistic details for GDI function with respect to RHO protein dynamics. We determined that membrane extraction of RHO GTPases by GDI occurs via a 3-step mechanism: (1) GDI non-specifically associates with the switch regions of the RHO GTPases; (2) an electrostatic switch determines the interaction specificity between the C-terminal polybasic region of RHO GTPases and two distinct negatively-charged clusters of GDI1; (3) a non-specific displacement of geranylgeranyl moiety from the membrane sequesters it into a hydrophobic cleft, effectively shielding it from the aqueous milieu. This study substantially extends the model for the mechanism of GDI-regulated RHO GTPase extraction from the membrane, and could have implications for clinical studies and drug development.

A DNA Nanoflower-Assisted Separation-Free Nucleic Acid Detection Platform with a Commercial Pregnancy Test Strip.

There is a constant drive for affordable point-of-care testing (POCT) technologies for the detection of infectious human diseases. Herein, we report a simple platform for DNA detection that takes advantage of four techniques: commercially available pregnancy test strips (PTS), amplicon generation via loop-mediated isothermal amplification (LAMP), toehold-mediated strand displacement, and noncovalent immobilization of DNA on paper surface with DNA nanoflowers. This simple, separation-free platform is highly specific, as demonstrated with the detection of rtL180M, a single-nucleotide polymorphism observed in hepatitis B virus (HBV) associated with antiviral drug resistance. It is very sensitive, capable of detecting the targeted mutation at 2 copies µL-1 . It is able to correctly identify the unmutated and rtL180M genome types of HBV in clinical samples. Given its wide adaptability, we expect this platform can be easily modified for the detection of genetic variations associated with various pathogens and human diseases.

Activating mutations in RRAS underlie a phenotype within the RASopathy spectrum and contribute to leukaemogenesis.

RASopathies, a family of disorders characterized by cardiac defects, defective growth, facial dysmorphism, variable cognitive deficits and predisposition to certain malignancies, are caused by constitutional dysregulation of RAS signalling predominantly through the RAF/MEK/ERK (MAPK) cascade. We report on two germline mutations (p.Gly39dup and p.Val55Met) in RRAS, a gene encoding a small monomeric GTPase controlling cell adhesion, spreading and migration, underlying a rare (2 subjects among 504 individuals analysed) and variable phenotype with features partially overlapping Noonan syndrome, the most common RASopathy. We also identified somatic RRAS mutations (p.Gly39dup and p.Gln87Leu) in 2 of 110 cases of non-syndromic juvenile myelomonocytic leukaemia, a childhood myeloproliferative/myelodysplastic disease caused by upregulated RAS signalling, defining an atypical form of this haematological disorder rapidly progressing to acute myeloid leukaemia. Two of the three identified mutations affected known oncogenic hotspots of RAS genes and conferred variably enhanced RRAS function and stimulus-dependent MAPK activation. Expression of an RRAS mutant homolog in Caenorhabditis elegans enhanced RAS signalling and engendered protruding vulva, a phenotype previously linked to the RASopathy-causing SHOC2(S2G) mutant. Overall, these findings provide evidence of a functional link between RRAS and MAPK signalling and reveal an unpredicted role of enhanced RRAS function in human disease.

Functional cross-talk between ras and rho pathways: a Ras-specific GTPase-activating protein (p120RasGAP) competitively inhibits the RhoGAP activity of deleted in liver cancer (DLC) tumor suppressor by masking the catalytic arginine finger.

The three deleted in liver cancer genes (DLC1-3) encode Rho-specific GTPase-activating proteins (RhoGAPs). Their expression is frequently silenced in a variety of cancers. The RhoGAP activity, which is required for full DLC-dependent tumor suppressor activity, can be inhibited by the Src homology 3 (SH3) domain of a Ras-specific GAP (p120RasGAP). Here, we comprehensively investigated the molecular mechanism underlying cross-talk between two distinct regulators of small GTP-binding proteins using structural and biochemical methods. We demonstrate that only the SH3 domain of p120 selectively inhibits the RhoGAP activity of all three DLC isoforms as compared with a large set of other representative SH3 or RhoGAP proteins. Structural and mutational analyses provide new insights into a putative interaction mode of the p120 SH3 domain with the DLC1 RhoGAP domain that is atypical and does not follow the classical PXXP-directed interaction. Hence, p120 associates with the DLC1 RhoGAP domain by targeting the catalytic arginine finger and thus by competitively and very potently inhibiting RhoGAP activity. The novel findings of this study shed light on the molecular mechanisms underlying the DLC inhibitory effects of p120 and suggest a functional cross-talk between Ras and Rho proteins at the level of regulatory proteins.

Diverging gain-of-function mechanisms of two novel KRAS mutations associated with Noonan and cardio-facio-cutaneous syndromes.

Activating somatic and germline mutations of closely related RAS genes (H, K, N) have been found in various types of cancer and in patients with developmental disorders, respectively. The involvement of the RAS signalling pathways in developmental disorders has recently emerged as one of the most important drivers in RAS research. In the present study, we investigated the biochemical and cell biological properties of two novel missense KRAS mutations (Y71H and K147E). Both mutations affect residues that are highly conserved within the RAS family. KRAS(Y71H) showed no clear differences to KRAS(wt), except for an increased binding affinity for its major effector, the RAF1 kinase. Consistent with this finding, even though we detected similar levels of active KRAS(Y71H) when compared with wild-type protein, we observed an increased activation of MEK1/2, irrespective of the stimulation conditions. In contrast, KRAS(K147E) exhibited a tremendous increase in nucleotide dissociation generating a self-activating RAS protein that can act independently of upstream signals. As a consequence, levels of active KRAS(K147E) were strongly increased regardless of serum stimulation and similar to the oncogenic KRAS(G12V). In spite of this, KRAS(K147E) downstream signalling did not reach the level triggered by oncogenic KRAS(G12V), especially because KRAS(K147E) was downregulated by RASGAP and moreover exhibited a 2-fold lower affinity for RAF kinase. Here, our findings clearly emphasize that individual RAS mutations, despite being associated with comparable phenotypes of developmental disorders in patients, can cause remarkably diverse biochemical effects with a common outcome, namely a rather moderate gain-of-function.

The cryo-EM structure of the BoNT/Wo-NTNH complex reveals two immunoglobulin-like domains.

The botulinum neurotoxin-like toxin from Weissella oryzae (BoNT/Wo) is one of the BoNT-like toxins recently identified outside of the Clostridium genus. We show that, like the canonical BoNTs, BoNT/Wo forms a complex with its non-toxic non-hemagglutinin (NTNH) partner, which in traditional BoNT serotypes protects the toxin from proteases and the acidic environment of the hosts' guts. We here report the cryo-EM structure of the 300 kDa BoNT/Wo-NTNH/Wo complex together with pH stability studies of the complex. The structure reveals molecular details of the toxin's interactions with its protective partner. The overall structural arrangement is similar to other reported BoNT-NTNH complexes, but NTNH/Wo uniquely contains two extra bacterial immunoglobulin-like (Big) domains on the C-terminus. Although the function of these Big domains is unknown, they are structurally most similar to bacterial proteins involved in adhesion to host cells. In addition, the BoNT/Wo protease domain contains an internal disulfide bond not seen in other BoNTs. Mass photometry analysis revealed that the BoNT/Wo-NTNH/Wo complex is stable under acidic conditions and may dissociate at neutral to basic pH. These findings established that BoNT/Wo-NTNH/Wo shares the general fold of canonical BoNT-NTNH complexes. The presence of unique structural features suggests that it may have an alternative mode of activation, translocation and recognition of host cells, raising interesting questions about the activity and the mechanism of action of BoNT/Wo as well as about its target environment, receptors and substrates.

Interaction characteristics of Plexin-B1 with Rho family proteins.

Plexin-B1 regulates various cellular processes interacting directly with several Rho proteins. Molecular details of these interactions are, however, not well understood. In this study, we examined in vitro and in silico the interaction of the Rho binding domain (B1RBD) of human Plexin-B1 with 11 different Rho proteins. We show that B1RBD binds in a GTP-dependent manner to Rac1, Rac2, Rac3, Rnd1, Rnd2, Rnd3, and RhoD, but not to RhoA, Cdc42, RhoG, or Rif. Interestingly, Rnd1 competitively displaces the Rac1 from B1RBD but not vice versa. Structure-function analysis revealed a negatively charged loop region, called B1L(31), which may facilitate a selective B1RBD interaction with Rho proteins.

Rho-kinase: regulation, (dys)function, and inhibition.

In a variety of normal and pathological cell types, Rho-kinases I and II (ROCKI/II) play a pivotal role in the organization of the nonmuscle and smooth muscle cytoskeleton and adhesion plaques as well as in the regulation of transcription factors. Thus, ROCKI/II activity regulates cellular contraction, motility, morphology, polarity, cell division, and gene expression. Emerging evidence suggests that dysregulation of the Rho-ROCK pathways at different stages is linked to cardiovascular, metabolic, and neurodegenerative diseases as well as cancer. This review focuses on the current status of understanding the multiple functions of Rho-ROCK signaling pathways and various modes of regulation of Rho-ROCK activity, thereby orchestrating a concerted functional response.

Dual targets-induced specific hemin/G-quadruplex assemblies for label-free electrochemical detection capable of distinguishing Salmonella and its common serotype in food samples.

Efficient detection of pathogenic bacteria is paramount for ensuring food safety and safeguarding public health. Herein, we developed a label-free and signal-on dual-target recognition electrochemical DNA sensing platform based on the conformational formation of split G-quadruplex. This platform focused on achieving sensitive and low-cost detection of Salmonella and its most human-infecting S. typhimurium serotype. In simple terms, the dual-target recognition probe (DTR-6P) was ingeniously designed for the loop sequence on the loop-mediated isothermal amplification (LAMP) amplicons. It could recognize two different genes and release their corresponding G-rich sequences. The exfoliated G-rich sequences could be captured by the capture probes on the electrode, and then the bimolecular G-quadruplex or the tetramolecular G-quadruplex would be formed to capture hemin, thereby enabling dual-signal reporting. The minimum detection amount of target genes can be as low as 2 copies/µL. Encouragingly, the real food samples contaminated by Salmonella and the S. typhimurium serotype can be readily identified. The sensing platform with ingenious design paves a new way for label-free, multi-target simultaneous detection, whose advantage of rapidity, sensitivity, cost-effectiveness, and specificity also lay a solid foundation for practical applications.

Structural basis for botulinum neurotoxin E recognition of synaptic vesicle protein 2.

Botulinum neurotoxin E (BoNT/E) is one of the major causes of human botulism and paradoxically also a promising therapeutic agent. Here we determined the co-crystal structures of the receptor-binding domain of BoNT/E (HCE) in complex with its neuronal receptor synaptic vesicle glycoprotein 2A (SV2A) and a nanobody that serves as a ganglioside surrogate. These structures reveal that the protein-protein interactions between HCE and SV2 provide the crucial location and specificity information for HCE to recognize SV2A and SV2B, but not the closely related SV2C. At the same time, HCE exploits a separated sialic acid-binding pocket to mediate recognition of an N-glycan of SV2. Structure-based mutagenesis and functional studies demonstrate that both the protein-protein and protein-glycan associations are essential for SV2A-mediated cell entry of BoNT/E and for its potent neurotoxicity. Our studies establish the structural basis to understand the receptor-specificity of BoNT/E and to engineer BoNT/E variants for new clinical applications.

OPRM1-ROS1 Fusion Detected by Next-Generation Sequencing with Circulating DNA in a Patient with EGFR Mutated Advanced NSCLC: A Case Report.

ROS1 comprises a small molecular subset of NSCLC, and several fusion partners have been discovered. Concomitant mutations of EGFR and ROS1 in NSCLC have been occasionally reported, while no clear standard of treatment has been revealed. Here we report a case with metastatic lung adenocarcinoma detected to have EGFR 21 exon L858R mutation at diagnosis, who responded to first-line gefitinib and second-line osimertinib treatment. Next-generation sequencing during the treatment course revealed multiple alterations, including an OPRM1-ROS1 Ointergenic: R36 fusion. We reviewed the related literatures but found no report of this fusion type previously. The application of ctDNA detection results in the finding of new alterations, which need further confirmation.

Single Domain Antibody application in bacterial infection diagnosis and neutralization.

Increasing antibiotic resistance to bacterial infections causes a serious threat to human health. Efficient detection and treatment strategies are the keys to preventing and reducing bacterial infections. Due to the high affinity and antigen specificity, antibodies have become an important tool for diagnosis and treatment of various human diseases. In addition to conventional antibodies, a unique class of "heavy-chain-only" antibodies (HCAbs) were found in the serum of camelids and sharks. HCAbs binds to the antigen through only one variable domain Referred to as VHH (variable domain of the heavy chain of HCAbs). The recombinant format of the VHH is also called single domain antibody (sdAb) or nanobody (Nb). Sharks might also have an ancestor HCAb from where SdAbs or V-NAR might be engineered. Compared with traditional Abs, Nbs have several outstanding properties such as small size, high stability, strong antigen-binding affinity, high solubility and low immunogenicity. Furthermore, they are expressed at low cost in microorganisms and amenable to engineering. These superior properties make Nbs a highly desired alternative to conventional antibodies, which are extensively employed in structural biology, unravelling biochemical mechanisms, molecular imaging, diagnosis and treatment of diseases. In this review, we summarized recent progress of nanobody-based approaches in diagnosis and neutralization of bacterial infection and further discussed the challenges of Nbs in these fields.

Delivery of single-domain antibodies into neurons using a chimeric toxin-based platform is therapeutic in mouse models of botulism.

Efficient penetration of cell membranes and specific targeting of a cell type represent major challenges for developing therapeutics toward intracellular targets. One example facing these hurdles is to develop post-exposure treatment for botulinum neurotoxins (BoNTs), a group of bacterial toxins (BoNT/A to BoNT/G) that are major potential bioterrorism agents. BoNTs enter motor neurons, block neurotransmitter release, and cause a paralytic disease botulism. Members of BoNTs such as BoNT/A exhibit extremely long half-life within neurons, resulting in persistent paralysis for months, yet there are no therapeutics that can inhibit BoNTs once they enter neurons. Here, we developed a chimeric toxin-based delivery platform by fusing the receptor-binding domain of a BoNT, which targets neurons, with the membrane translocation domain and inactivated protease domain of the recently discovered BoNT-like toxin BoNT/X, which can deliver cargoes across endosomal membranes into the cytosol. A therapeutic protein was then created by fusing a single-domain antibody (nanobody) against BoNT/A with the delivery platform. In vitro characterization demonstrated that nanobodies were delivered into cultured neurons and neutralized BoNT/A in neurons. Administration of this protein in mice shortened duration of local muscle paralysis, restoring muscle function within hours, and rescued mice from systemic toxicity of lethal doses of BoNT/A. Fusion of two nanobodies, one against BoNT/A and the other against BoNT/B, created a multivalent therapeutic protein able to neutralize both BoNT/A and BoNT/B in mice. These studies provide an effective post-exposure treatment for botulism and establish a platform for intracellular delivery of therapeutics targeting cytosolic proteins and processes.

UBE2S promotes cell chemoresistance through PTEN-AKT signaling in hepatocellular carcinoma.

Ubiquitination displays a crucial role in various biological functions, such as protein degradation, signal transduction, and cellular homeostasis. Accumulating evidence has indicated that ubiquitination is essential in cancer progression. Ubiquitin-conjugating enzyme E2S (UBE2S) is a member of ubiquitin-conjugating enzyme family of the ubiquitin system and its role in hepatocellular cancer (HCC) is largely unknown. We investigated the role of UBE2S in HCC and found UBE2S upregulation is relevant with large tumor size, recurrence, and advanced TNM stage, serving as an independent risk factor of overall survival (OS) and disease-free survival (DFS) for HCC patients. We conducted in vitro experiments and found that in HCC cells, UBE2S overexpression increases the resistance to 5-FU and oxaliplatin, while UBE2S knockdown achieves an opposite effect. UBE2S is transcriptionally activated by the binding of FOXM1 to UBE2S promoter, which induces its upregulation and reduces PTEN protein level by promoting PTEN ubiquitination at Lys60 and Lys327 and facilitating AKT phosphorylation. The promotional effect of FOXM1-UBE2S axis on HCC cell chemoresistance is attenuated by allosteric AKT inhibitor, MK2206. In conclusion, our results reveal that UBE2S is a prognostic biomarker for HCC patients, and the FOXM1-UBE2S-PTEN-p-AKT signaling axis might be a promising target for the treatment of HCC.

Structural basis for selective modification of Rho and Ras GTPases by Clostridioides difficile toxin B.

Toxin B (TcdB) is a primary cause of Clostridioides difficile infection (CDI). This toxin acts by glucosylating small GTPases in the Rho/Ras families, but the structural basis for TcdB recognition and selectivity of specific GTPase substrates remain unsolved. Here, we report the cocrystal structures of the glucosyltransferase domain (GTD) of two distinct TcdB variants in complex with human Cdc42 and R-Ras, respectively. These structures reveal a common structural mechanism by which TcdB recognizes Rho and R-Ras. Furthermore, we find selective clustering of adaptive residue changes in GTDs that determine their substrate preferences, which helps partition all known TcdB variants into two groups that display distinct specificities toward Rho or R-Ras. Mutations that selectively disrupt GTPases binding reduce the glucosyltransferase activity of the GTD and the toxicity of TcdB holotoxin. These findings establish the structural basis for TcdB recognition of small GTPases and reveal strategies for therapeutic interventions for CDI.

Phage-assisted evolution of botulinum neurotoxin proteases with reprogrammed specificity.

Although bespoke, sequence-specific proteases have the potential to advance biotechnology and medicine, generation of proteases with tailor-made cleavage specificities remains a major challenge. We developed a phage-assisted protease evolution system with simultaneous positive and negative selection and applied it to three botulinum neurotoxin (BoNT) light-chain proteases. We evolved BoNT/X protease into separate variants that preferentially cleave vesicle-associated membrane protein 4 (VAMP4) and Ykt6, evolved BoNT/F protease to selectively cleave the non-native substrate VAMP7, and evolved BoNT/E protease to cleave phosphatase and tensin homolog (PTEN) but not any natural BoNT protease substrate in neurons. The evolved proteases display large changes in specificity (218- to >11,000,000-fold) and can retain their ability to form holotoxins that self-deliver into primary neurons. These findings establish a versatile platform for reprogramming proteases to selectively cleave new targets of therapeutic interest.