Biophysical Characterization of RAS-SOS Complexes by Native Mass Spectrometry.

RAS is regulated by specific guanine nucleotide exchange factors, such as Son of Sevenless (SOS), that activates RAS by facilitating the exchange of inactive, GDP-bound RAS with GTP. The catalytic activity of SOS is known to be allosterically modulated by an active, GTP-bound RAS. However, it remains poorly understood how oncogenic RAS mutants interact with SOS and modulate its activity. In this chapter, we describe the application of native mass spectrometry (MS) to monitor the assembly of the catalytic domain of SOS (SOScat) with RAS and cancer-associated mutants. Results from this approach have led to the discovery of different molecular assemblies and distinct conformers of SOScat engaging KRAS. It was also found that KRASG13D exhibits high affinity for SOScat and is a potent allosteric modulator of its SOScat activity. KRASG13D-GTP can allosterically increase the nucleotide exchange rate of KRAS at the active site by more than twofold compared to the wild-type protein. Furthermore, small-molecule RAS•SOS disruptors fail to dissociate KRASG13D•SOScat complexes, underscoring the need for more potent disruptors targeting oncogenic RAS mutants. Taken together, native MS will be instrumental in better understanding the interaction between oncogenic RAS mutants and SOS, which is of crucial importance for development of improved therapeutics.

Native mass spectrometry of proteoliposomes containing integral and peripheral membrane proteins.

Cellular membranes are critical to the function of membrane proteins, whether they are associated (peripheral) or embedded (integral) within the bilayer. While detergents have contributed to our understanding of membrane protein structure and function, there remains challenges in characterizing protein-lipid interactions within the context of an intact membrane. Here, we developed a method to prepare proteoliposomes for native mass spectrometry (MS) studies. We first use native MS to detect the encapsulation of soluble proteins within liposomes. We then find the peripheral Gß1γ2 complex associated with the membrane can be ejected and analyzed using native MS. Four different integral membrane proteins (AmtB, AqpZ, TRAAK, and TREK2), all of which have previously been characterized in detergent, eject from the proteoliposomes as intact complexes bound to lipids that have been shown to tightly associate in detergent, drawing a correlation between the two approaches. We also show the utility of more complex lipid environments, such as a brain polar lipid extract, and show TRAAK ejects from liposomes of this extract bound to lipids. These findings underscore the capability to eject protein complexes from membranes bound to both lipids and metal ions, and this approach will be instrumental in the identification of key protein-lipid interactions.

Factors Associated with Spontaneous Preterm Birth after Ultrasound-Indicated Cerclage.

Ultrasound-indicated cerclage (UIC) is recommended to prevent spontaneous preterm birth (sPTB) in women with a short cervix at mid-trimester and a history of PTB. We assessed the factors related to sPTB after UIC and determined the corresponding risks. This retrospective cohort study was conducted at a university hospital. UIC was performed between 15 and 26 weeks of gestation in women with a cervical length of <2.5 cm. Univariate and multivariate analyses were used to examine factors associated with sPTB after UIC. An earlier gestational age and shorter cervical length at UIC were associated with sPTB after UIC. While PTB history was not associated with an increased risk of sPTB, it did increase the risk of repeat cerclage after UIC. Higher levels of preoperative serum inflammatory markers and obesity significantly increased the risk of sPTB after UIC. These findings provide helpful guidance for patient counseling and management in predicting the delivery timing after UIC in women with a short cervix in the mid-trimester.

2'-Deoxy Guanosine Nucleotides Alter the Biochemical Properties of Ras.

Ras proteins in the mitogen-activated protein kinase (MAPK) signaling pathway represent one of the most frequently mutated oncogenes in cancer. Ras binds guanosine nucleotides and cycles between active (GTP) and inactive (GDP) conformations to regulate the MAPK signaling pathway. Guanosine and other nucleotides exist in cells as either 2'-hydroxy or 2'-deoxy forms, and imbalances in the deoxyribonucleotide triphosphate pool have been associated with different diseases, such as diabetes, obesity, and cancer. However, the biochemical properties of Ras bound to dGNP are not well understood. Herein, we use native mass spectrometry to monitor the intrinsic GTPase activity of H-Ras and N-Ras oncogenic mutants, revealing that the rate of 2'-deoxy guanosine triphosphate (dGTP) hydrolysis differs compared to the hydroxylated form, in some cases by seven-fold. Moreover, K-Ras expressed from HEK293 cells exhibited a higher than anticipated abundance of dGNP, despite the low abundance of dGNP in cells. Additionally, the GTPase and dGTPase activity of K-RasG12C was found to be accelerated by 10.2- and 3.8-fold in the presence of small molecule covalent inhibitors, which may open opportunities for the development of Pan-Ras inhibitors. The molecular assemblies formed between H-Ras and N-Ras, including mutant forms, with the catalytic domain of SOS (SOScat) were also investigated. The results show that the different mutants of H-Ras and N-Ras not only engage SOScat differently, but these assemblies are also dependent on the form of guanosine triphosphate bound to Ras. These findings bring to the forefront a new perspective on the nucleotide-dependent biochemical properties of Ras that may have implications for the activation of the MAPK signaling pathway and Ras-driven cancers.

GNSS land subsidence observations along the northern coastline of Java, Indonesia.

Land subsidence in cities along the northern coastline of Java has been at a worrying level. Monitoring efforts using geodetic data reveal that Jakarta, Pekalongan, Semarang, and Demak subside at least ~9x faster than the present-day rate of global sea level rise, which affects the cities' future urban viability. In this study, we publish a time series of the precise 3D displacements observed by twenty continuous Global Navigation Satellite System (GNSS) stations between 2010 and 2021. These are the first open-to-the-public and rigorously processed GNSS datasets that are useful for accurately quantifying land subsidence in the densely populated sinking cities in Java. The data also provides a way to tie other geodetic observations, such as Interferometric Synthetic Aperture Radar (InSAR), to a global reference frame in an attempt to build worldwide observations of coastal land subsidence.

Rapid flood and damage mapping using synthetic aperture radar in response to Typhoon Hagibis, Japan.

During the aftermath of Typhoon Hagibis, we made flood and damage proxy maps, rapidly derived from synthetic aperture radar (SAR) data using change detection approaches. The maps have large spatial coverage over the Tokyo, Fukushima, Ibaraki, Iwate, and Nagano prefectures of Japan. The maps are also largely in agreement with various validation sources including aerial imagery, optical imagery and news sources. Apart from visual maps, we provide flood and damage extents in various formats compatible with geographic information system (GIS) applications. The data may potentially be used for applications such as typhoon risk modelling, investigating spatial correlations of typhoon impacts, and comparing alternative flood or damage mapping techniques.

Hierarchical interlocked orthogonal faulting in the 2019 Ridgecrest earthquake sequence.

A nearly 20-year hiatus in major seismic activity in southern California ended on 4 July 2019 with a sequence of intersecting earthquakes near the city of Ridgecrest, California. This sequence included a foreshock with a moment magnitude (M w) of 6.4 followed by a M w 7.1 mainshock nearly 34 hours later. Geodetic, seismic, and seismicity data provided an integrative view of this sequence, which ruptured an unmapped multiscale network of interlaced orthogonal faults. This complex fault geometry persists over the entire seismogenic depth range. The rupture of the mainshock terminated only a few kilometers from the major regional Garlock fault, triggering shallow creep and a substantial earthquake swarm. The repeated occurrence of multifault ruptures, as revealed by modern instrumentation and analysis techniques, poses a formidable challenge in quantifying regional seismic hazards.

Retrieving Precise Three-Dimensional Deformation on the 2014 M6.0 South Napa Earthquake by Joint Inversion of Multi-Sensor SAR.

We reconstructed the three-dimensional (3D) surface displacement field of the 24 August 2014 M6.0 South Napa earthquake using SAR data from the Italian Space Agency's COSMO-SkyMed and the European Space Agency's Sentinel-1A satellites. Along-track and cross-track displacements produced with conventional SAR interferometry (InSAR) and multiple-aperture SAR interferometry (MAI) techniques were integrated to retrieve the east, north, and up components of surface deformation. The resulting 3D displacement maps clearly delineated the right-lateral shear motion of the fault rupture with a maximum surface displacement of approximately 45 cm along the fault's strike, showing the east and north components of the trace particularly clearly. These maps also suggested a better-constrained model for the South Napa earthquake. We determined a strike of approximately 338° and dip of 85° by applying the Okada dislocation model considering a single patch with a homogeneous slip motion. Using the distributed slip model obtained by a linear solution, we estimated that a peak slip of approximately 1.7 m occurred around 4 km depth from the surface. 3D modelling using the retrieved 3D maps helps clarify the fault's nature and thus characterize its behaviour.

Changes in Eyebrow Position and Movement with Aging.

BACKGROUND: This study evaluated dynamic changes in eyebrow position related to aging. METHODS: Female participants were recruited and separated into two groups aged 20-30 years (the younger group, n=20; mean age, 24.8 years) and 50-70 years (the older group, n=20; mean age, 55.8 years). Photogrammetry was used to determine the eyebrow position at the medial canthus (MC), lateral limbus, lateral canthus, and lateral end point (EP) for 6 actions: smooth opening (the reference action) and closing of the eye, forward gaze, maximum opening and closing of the eye, and maximum frown. Videos were also recorded. RESULTS: No differences in eyebrow position were detected at the MC when opening or closing the eyes smoothly, gazing straight ahead, or closing the eyes maximally. For all 6 actions, the position of the lateral EP in the older group was significantly lower than in the younger group (P=0.003), and the smallest degree of vertical movement at this point was found in both age groups (P<0.001). Vertical movement at the 4 landmarks of the eyebrows decreased with aging. CONCLUSIONS: Eyebrow position was unchanged at the MC with aging, except at maximal eye opening and maximal frown. No differences in eyebrow position were observed between the younger and older groups when eyes were maximally closed, except at the EP. It is important to focus on correction of the lateral EP for periorbital rejuvenation.

An efficient mosaic algorithm considering seasonal variation: application to KOMPSAT-2 satellite images.

As the aerospace industry grows, images obtained from Earth observation satellites have been successfully used in various fields. Specifically, the demand for a high-resolution (HR) optical images is gradually increasing, and hence the generation of a high-quality mosaic image is being magnified as an interesting issue. In this paper, we have proposed an efficient mosaic algorithm for HR optical images that are significantly different due to seasonal change. The algorithm includes main steps such as: (1) seamline extraction from gradient magnitude and seam images; (2) histogram matching; and (3) image feathering. Eleven Kompsat-2 images characterized by seasonal variations are used for the performance validation of the proposed method. The results of the performance test show that the proposed method effectively mosaics Kompsat-2 adjacent images including severe seasonal changes. Moreover, the results reveal that the proposed method is applicable to HR optic images such as GeoEye, IKONOS, QuickBird, RapidEye, SPOT, WorldView, etc.

Changes of eyebrow muscle activity with aging: functional analysis revealed by electromyography.

BACKGROUND: This study evaluated the activity of the frontalis muscle, the corrugator supercilii muscle, and the orbicularis oculi muscle according to eyebrow movement and aging. METHODS: Two random cohorts of women aged 20 to 30 years (young group, n = 20; mean age, 24.8 years) and 50 to 70 years (old group, n = 20; mean age, 55.8 years) were recruited prospectively. Surface electromyography was used to evaluate motor unit action potential for each muscle in each of six eyebrow movements. Details on statistical analysis are described in the text. RESULTS: In both age groups, corrugator supercilii muscle activity was the highest for all six movements. Frontalis muscle activity was highest with maximal frowning but not with maximal eye opening. Orbicularis oculi muscle activity was significantly greater in the older age group than in the younger age group for most actions. When the motion proportion of each muscle was compared, the respective orbicularis oculi muscle and corrugator supercilii muscle indices were higher in the older age group than in the young group. CONCLUSIONS: Eyebrows are maintained by the dynamic balance of frontalis, corrugator supercilii, and orbicularis oculi muscles, and various combinations of motor recruitment of these muscles determine the eyebrow position and shape. For youthful eyebrows, attenuation of the depressor muscle may restore the muscle balance in treatments for eyebrow rejuvenation.

Large auricular chondrocutaneous composite graft for nasal alar and columellar reconstruction.

BACKGROUND: Among the various methods for correcting nasal deformity, the composite graft is suitable for the inner and outer reconstruction of the nose in a single stage. In this article, we present our technique for reconstructing the ala and columella using the auricular chondrocutaneous composite graft. METHODS: From 2004 to 2011, 15 cases of alar and 2 cases of columellar reconstruction employing the chondrocutaneous composite graft were studied, all followed up for 3 to 24 months (average, 13.5 months). All of the patients were reviewed retrospectively for the demographics, graft size, selection of the donor site and outcomes including morbidity and complications. RESULTS: The reasons for the deformity were burn scar (n=7), traumatic scar (n=4), smallpox scar (n=4), basal cell carcinoma defect (n=1), and scar contracture (n=1) from implant induced infection. In 5 cases of nostril stricture and 6 cases of alar defect and notching, composite grafts from the helix were used (8.9×12.5 mm). In 4 cases of retracted ala, grafts from the posterior surface of the concha were matched (5×15 mm). For the reconstruction of the columella, we harvested the graft from the posterior scapha (9×13.5 mm). Except one case with partial necrosis and delayed healing due to smoking, the grafts were successful in all of the cases and there was no deformity of the donor site. CONCLUSIONS: An alar and columellar defect can be reconstructed successfully with a relatively large composite graft without donor site morbidity. The selection of the donor site should be individualized according to the 3-dimensional configuration of the defect.

Stress control of deep rift intrusion at Mauna Loa volcano, Hawaii.

Mauna Loa volcano, Hawaii, deforms by a combination of shallow dike intrusions in the rift zones and earthquakes along the base of the volcano, but it is not known how the spreading is accommodated in the lower part of the volcanic edifice. We present evidence from interferometric synthetic aperture radar data for secular inflation of a dike-like magma body at intermediate depth in the southwest rift zone during 2002 to 2005. Magma accumulation occurred in a section of the rift zone that was unclamped by previous dikes and earthquakes, suggesting that stress transfer plays an important role in controlling subsurface magma accumulation.