GEFS

Breast cancer continues to pose a substantial global health challenge, emphasizing the critical need for the advancement of novel therapeutic approaches. Key players in the regulation of apoptosis, a fundamental process in cell death, are the B-cell lymphoma 2 (Bcl-2) family proteins, namely Bcl-2 and Bax. These proteins have garnered attention as highly promising targets for the treatment of breast cancer. Targeting the overexpressed anti-apoptotic Bcl-2 protein in breast cancer, Gefitinib (GEF), an EGFR (Epidermal Growth Factor Receptor) inhibitor, emerges as a potential solution...

Genome editing technologies such as CRISPR/Cas9 have been developed in the last decade and have been applied to new food technologies. Genome-edited food (GEF) is a crucial issue with those new food technologies. Thus, each country has established GEF governance systems to maximize benefits and minimize risks. These emphasize the importance of communicating about GEF to the public. The key concerns are understanding various viewpoints and value perspectives (framings) in science and technology and encouraging and opening communication with the public...

Tight junctions are a barrier-forming cell-cell adhesion complex and have been proposed to regulate cell proliferation. However, the underlying mechanisms are not well understood. Here, we used cells deficient in the junction scaffold ZO-1 alone or together with its paralog ZO-2, which disrupts the junctional barrier. We found that ZO-1 knockout increased cell proliferation, induced loss of cell density-dependent proliferation control, and promoted apoptosis and necrosis. These phenotypes were enhanced by double ZO-1/ZO-2 knockout...

Activation of heterotrimeric G-proteins (Gαβγ) downstream to receptor tyrosine kinases (RTKs) is a well-established crosstalk between the signaling pathways mediated by G-protein coupled receptors (GPCRs) and RTKs. While GPCR serves as a guanine exchange factor (GEF) in the canonical activation of Gα that facilitates the exchange of GDP for GTP, the mechanism through which RTK phosphorylations induce Gα activation remains unclear. Recent experimental studies revealed that the epidermal growth factor receptor (EGFR), a well-known RTK, phosphorylates the helical domain tyrosine residues Y154 and Y155 and accelerates the GDP release from the Gαi3, a subtype of Gα-protein...

SGEF, a RhoG specific GEF, can form a ternary complex with the Scribble polarity complex proteins Scribble and Dlg1, which regulates the formation and maintenance of adherens junctions and barrier function of epithelial cells. Notably, silencing SGEF results in a dramatic downregulation of the expression of both E-cadherin and ZO-1. However, the molecular mechanisms involved in the regulation of this pathway are not known. Here, we describe a novel signaling pathway governed by the Scribble/SGEF/Dlg1 complex...

Opioid pain medications, such as morphine, remain the mainstay for treating severe and chronic pain. Prolonged morphine use, however, triggers analgesic tolerance and hyperalgesia (OIH), which can last for a long period after morphine withdrawal. How morphine induces these detrimental side effects remains unclear. Here, we show that morphine tolerance and OIH are mediated by Tiam1-coordinated synaptic structural and functional plasticity in the spinal nociceptive network. Tiam1 is a Rac1 GTPase guanine nucleotide exchange factor (GEF) that promotes excitatory synaptogenesis by modulating actin cytoskeletal dynamics...

The ADP-ribosylation factors (Arfs) constitute a family of small GTPases within the Ras superfamily, with a distinguishing structural feature of a hypervariable N-terminal extension of the G domain modified with myristate. Arf proteins, including Arf1, have roles in membrane trafficking and cytoskeletal dynamics. While screening for Arf1:small molecule co-crystals, we serendipitously solved the crystal structure of the non-myristoylated engineered mutation [L8K]Arf1 in complex with a GDP analogue. Like wild-type (WT) non-myristoylated Arf1•GDP, we observed that [L8K]Arf1 exhibited an N-terminal helix that occludes the hydrophobic cavity that is occupied by the myristoyl group in the GDP-bound state of the native protein...

The activation level of RAS can be determined by GTP hydrolysis rate (khy ) and GDP-GTP exchange rates (kex ). Either impaired GTP hydrolysis or enhanced GDP-GTP exchange causes the aberrant activation of RAS in oncogenic mutants. Therefore, it is important to quantify the khy and kex for understanding the mechanisms of RAS oncogenesis and drug development. Conventional methods have individually measured the kex and khy of RAS. However, within the intracellular environment, GTP hydrolysis and GDP-GTP exchange reactions occur simultaneously under conditions where GTP concentration is kept constant...

Knowledge of how effectors interact with RAS GTPases is key to understanding how these switch-like proteins function in cells. Effectors bind specifically to GTP-loaded RAS using RAS association (RA) or RAS binding domains (RBDs) that show wide-ranging affinities and thermodynamic characteristics. Both normal development and RAS-induced tumorigenesis depend on multiple distinct effector proteins that are frequently co-expressed and co-localized, suggesting an antagonistic nature to signaling whereby multiple proteins compete for a limited pool of activated GTPase...

Guanine nucleotide-exchange factors ( GEFs ) genes play key roles in plant root and pollen tube growth, phytohormone responses, and abiotic stress responses. RopGEF genes in Brassica rapa have not yet been explored. Here, GEF genes were found to be distributed across eight chromosomes in B. rapa and were classified into three subfamilies. Promoter sequence analysis of BrRopGEFs revealed the presence of cis -elements characteristic of BrRopGEF promoters, and these cis -elements play a role in regulating abiotic stress tolerance and stress-related hormone responses...

Organelles of the endomembrane system contain Rab GTPases as identity markers. Their localization is determined by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). It remains largely unclear how these regulators are specifically targeted to organelles and how their activity is regulated. Here, we focus on the GAP Gyp7, which acts on the Rab7-like Ypt7 protein in yeast, and surprisingly observe the protein exclusively in puncta proximal to the vacuole. Mistargeting of Gyp7 to the vacuole strongly affects vacuole morphology, suggesting that endosomal localization is needed for function...

Highly homologous members of the Gαi family, Gαi1-3 , have distinct tissue distributions and physiological functions, yet their biochemical and functional properties are very similar. We recently identified PDZ-RhoGEF (PRG) as a novel Gαi1 effector that is poorly activated by Gαi2 . In a proteomic proximity labeling screen we observed a strong preference for Gαi1 relative to Gαi2 with respect to engagement of a broad range of potential targets. We investigated the mechanistic basis for this selectivity using PRG as a representative target...

Purpose Ultrasound-guided puncture and punch biopsy pose a particular challenge in the training of ultrasound examination. These techniques should be learned and performed several times before being applied to the patient using a simulation model that is as realistic as possible. While the use of agar-agar-based models is extensively documented in the literature, there is a discernible gap in publications specifically addressing their use in punch biopsy and puncture. The aim was to develop a cost-effective model for the simulation of ultrasound-guided interventions...

BACKGROUND: A pathogenic variant in SCN1A can result in a spectrum of phenotypes, including Dravet syndrome (DS) and genetic epilepsy with febrile seizures plus (GEFS + ) syndrome. Dravet syndrome (DS) is associated with refractory seizures, developmental delay, intellectual disability (ID), motor impairment, and challenging behavior(1,2). GEFS + is a less severe phenotype in which cognition is often normal and seizures are less severe. Challenging behavior largely affects quality of life of patients and their families...

Cell polarity oscillations in Myxococcus xanthus motility are driven by a prokaryotic small Ras-like GTPase, MglA, which switches from one cell pole to the other in response to extracellular signals. MglA dynamics is regulated by MglB, which functions both as a GAP (GTPase activating protein) and a GEF (guanine nucleotide exchange factor) for MglA. With an aim to dissect the asymmetric role of the two MglB protomers in the dual GAP and GEF activities, we generated a functional MglAB complex by co-expressing MglB with a linked construct of MglA and MglB...

Natural killer (NK) cells have the ability to lyse other cells through the release of lytic granules (LG). This is in part mediated by the small GTPase Rab27a, which was first identified to play a critical role in degranulation through the study of patients harboring mutations in the gene encoding Rab27a. However, the guanine nucleotide exchange factor (GEF) regulating the activation of Rab27a in cytotoxic lymphocytes was unknown. Here we show that knockout of MADD significantly decreased GTP-bound Rab27a in both resting and stimulated NK cells, and MADD-deficient NK cells and CD8+ T cells displayed severely reduced degranulation and cytolytic ability, similar to that seen with Rab27a deficiency...

Yeast Rho5 is a small GTPase which mediates the response to nutrient and oxidative stress, and triggers mitophagy and apoptosis. We here studied the rapid translocation of a GFP-tagged Rho5 to mitochondria under such stress conditions by live-cell fluorescence microscopy in the background of strains lacking different mitochondrial outer membrane proteins (MOMP). Fun14, Msp1 and Alo1 were found to be required for efficient recruitment of the GTPase, whereas translocation of Dck1 and Lmo1, the subunits of its dimeric GDP/GTP exchange factor (GEF), remained unaffected...

Genetic factors contribute to the aetiology of epilepsy in >50% of cases, and information on the use of antiseizure medications in people with specific aetiologies will help guide treatment decisions. The PERMIT Extension study pooled data from two real-world studies (PERMIT and PROVE) to investigate the effectiveness and safety/tolerability of perampanel (PER) when used to treat people with focal and generalised epilepsy in everyday clinical practice. This post-hoc analysis of PERMIT Extension explored the use of PER when used to treat individuals presumed to have epilepsy with a genetic aetiology...

BACKGROUND: Haploidentical (Haplo) HCT for nonmalignant diseases (NMD) faces inherent challenges of both alloreactivity and graft failure. Building upon promising results from pilot studies, where abatacept was combined with post-transplantation cyclophosphamide (PTCy) and sirolimus (AbaCyS) in younger NMD patients undergoing haplo-HCT, we present the long-term outcomes of this protocol. STUDY DESIGN: On the back of uniform disease-specific conditioning regimens containing ATG (4...

Trastuzumab and trastuzumab-based treatments are the standard of care for breast cancer patients who overexpress the human epidermal growth factor receptor 2 (HER2). However, patients often develop resistance to trastuzumab via signaling from alternative growth factor receptors that converge to activate guanine nucleotide exchange factors (GEFs) that in turn activate the Rho GTPases Rac and Cdc42. Since Rac and Cdc42 have been implicated in high tumor grade and therapy resistance, inhibiting the activity of Rac and Cdc42 is a rational strategy to overcome HER2-targeted therapy resistance...