The UFM1 Pathway Impacts HCMV US2-Mediated Degradation of HLA Class I

To prevent accumulation of misfolded proteins in the endoplasmic reticulum, chaperones perform quality control on newly translated proteins and redirect misfolded proteins to the cytosol for degradation by the ubiquitin-proteasome system. This pathway is called ER-associated protein degradation (ERAD). The human cytomegalovirus protein US2 induces accelerated ERAD of HLA class I molecules to prevent immune recognition of infected cells by CD8(+) T cells. Using US2-mediated HLA-I degradation as a model for ERAD, we performed a genome-wide CRISPR/Cas9 library screen to identify novel cellular factors associated with ERAD. Besides the identification of known players such as TRC8, p97, and UBE2G2, the ubiquitin-fold modifier1 (UFM1) pathway was found to affect degradation of HLA-I. UFMylation is a post-translational modification resembling ubiquitination. Whereas we observe ubiquitination of HLA-I, no UFMylation was detected on HLA-I or several other proteins involved in degradation of HLA-I, suggesting that the UFM1 pathway impacts ERAD in a different manner than ubiquitin. Interference with the UFM1 pathway seems to specifically inhibit the ER-to-cytosol dislocation of HLA-I. In the absence of detectable UFMylation of HLA-I, UFM1 may contribute to US2-mediated HLA-I degradation by misdirecting protein sorting indirectly. Mass spectrometry analysis of US2-expressing cells showed that ribosomal proteins are a major class of proteins undergoing extensive UFMylation; the role of these changes in protein degradation may be indirect and remains to be established.This article belongs to the Special Issue Ubiquitin and Ubiquitin-Like Proteins: From Basic Mechanisms to Human Disorder

Reduced incorporation of Fatty acids into triacylglycerol in myotubes from obese individuals with type 2 diabetes.

Altered skeletal muscle lipid metabolism is a hallmark feature of type 2 (T2D). Here we investigated muscle lipid turnover in T2D versus BMI- controls and examined if putative in vivo differences would be preserved myotubes.Male obese T2D individuals (T2D) (n=6) and their BMI-matched (C) (n=6) underwent a hyperinsulinemic-euglycemic clamp, VO2max test, underwater weighing and muscle biopsy of v. lateralis. 14C-palmitate and 14C-oleate oxidation rates and incorporation into lipids were measured tissue, as well as in primary myotubes.Palmitate oxidation (C: 0.99 +/- T2D: 0.53 +/- 0.07nmol/mg protein; P=0.03) and incorporation of fatty into triacylglycerol (TAG) (C: 0.45 +/- 0.13, T2D: 0.11 +/- 0.02nmol/mg P=0.047) were significantly reduced in muscle homogenates of T2D. These reductions were not retained for palmitate oxidation in primary myotubes (P=0.38); however, incorporation of FAs into TAG was lower in T2D oleate and P=0.11 for palmitate), with a strong correlation of TAG between muscle tissue and primary myotubes (r=0.848, P=0.008).Our data that the ability to incorporate FAs into TAG is an intrinsic feature of muscle cells that is reduced in individuals with T2D

Sensitivity of the Atlantic meridional overturning circulation to South Atlantic freshwater anomalies

The sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) to changes in basin integrated net evaporation is highly dependent on the zonal salinity contrast at the southern border of the Atlantic. Biases in the freshwater budget strongly affect the stability of the AMOC in numerical models. The impact of these biases is investigated, by adding local anomaly patterns in the South Atlantic to the freshwater fluxes at the surface. These anomalies impact the freshwater and salt transport by the different components of the ocean circulation, in particular the basin-scale salt-advection feedback, completely changing the response of the AMOC to arbitrary perturbations. It is found that an appropriate dipole anomaly pattern at the southern border of the Atlantic Ocean can collapse the AMOC entirely even without a further hosing. The results suggest a new view on the stability of the AMOC, controlled by processes in the South Atlantic. <br/

Introducing the DizzyQuest: an app-based diary for vestibular disorders

BACKGROUND Most questionnaires currently used for assessing symptomatology of vestibular disorders are retrospective, inducing recall bias and lowering ecological validity. An app-based diary, administered multiple times in daily life, could increase the accuracy and ecological validity of symptom measurement. The objective of this study was to introduce a new experience sampling method (ESM) based vestibular diary app (DizzyQuest), evaluate response rates, and to provide examples of DizzyQuest outcome measures which can be used in future research. METHODS Sixty-three patients diagnosed with a vestibular disorder were included. The DizzyQuest consisted of four questionnaires. The morning- and evening-questionnaires were administered once each day, the within-day-questionnaire 10 times a day using a semi-random time schedule, and the attack questionnaire could be completed after the occurrence of a vertigo or dizziness attack. Data were collected for 4~weeks. Response rates and loss-to-follow-up were determined. Reported symptoms in the within-day-questionnaire were compared within and between patients and subgroups of patients with different vestibular disorders. RESULTS Fifty-one patients completed the study period. Average response rates were significantly higher than the desired response rate of \textgreater 50% (p \textless 0.001). The attack-questionnaire was used 159 times. A variety of neuro-otological symptoms and different disease profiles were demonstrated between patients and subgroups of patients with different vestibular disorders. CONCLUSION The DizzyQuest is able to capture vestibular symptoms within their psychosocial context in daily life, with little recall bias and high ecological validity. The DizzyQuest reached the desired response rates and showed different disease profiles between subgroups of patients with different vestibular disorders. This is the first time ESM was used to assess daily symptoms and quality of life in vestibular disorders, showing that it might be a useful tool in this population

The UFM1 Pathway Impacts HCMV US2-Mediated Degradation of HLA Class I

To prevent accumulation of misfolded proteins in the endoplasmic reticulum, chaperones perform quality control on newly translated proteins and redirect misfolded proteins to the cytosol for degradation by the ubiquitin-proteasome system. This pathway is called ER-associated protein degradation (ERAD). The human cytomegalovirus protein US2 induces accelerated ERAD of HLA class I molecules to prevent immune recognition of infected cells by CD8(+) T cells. Using US2-mediated HLA-I degradation as a model for ERAD, we performed a genome-wide CRISPR/Cas9 library screen to identify novel cellular factors associated with ERAD. Besides the identification of known players such as TRC8, p97, and UBE2G2, the ubiquitin-fold modifier1 (UFM1) pathway was found to affect degradation of HLA-I. UFMylation is a post-translational modification resembling ubiquitination. Whereas we observe ubiquitination of HLA-I, no UFMylation was detected on HLA-I or several other proteins involved in degradation of HLA-I, suggesting that the UFM1 pathway impacts ERAD in a different manner than ubiquitin. Interference with the UFM1 pathway seems to specifically inhibit the ER-to-cytosol dislocation of HLA-I. In the absence of detectable UFMylation of HLA-I, UFM1 may contribute to US2-mediated HLA-I degradation by misdirecting protein sorting indirectly. Mass spectrometry analysis of US2-expressing cells showed that ribosomal proteins are a major class of proteins undergoing extensive UFMylation; the role of these changes in protein degradation may be indirect and remains to be established

Unveiling the Power of Deep Tracking

In the field of generic object tracking numerous attempts have been made to exploit deep features. Despite all expectations, deep trackers are yet to reach an outstanding level of performance compared to methods solely based on handcrafted features. In this paper, we investigate this key issue and propose an approach to unlock the true potential of deep features for tracking. We systematically study the characteristics of both deep and shallow features, and their relation to tracking accuracy and robustness. We identify the limited data and low spatial resolution as the main challenges, and propose strategies to counter these issues when integrating deep features for tracking. Furthermore, we propose a novel adaptive fusion approach that leverages the complementary properties of deep and shallow features to improve both robustness and accuracy. Extensive experiments are performed on four challenging datasets. On VOT2017, our approach significantly outperforms the top performing tracker from the challenge with a relative gain of 17% in EAO

Combining Image-Level and Segment-Level Models for Automatic Annotation

Abstract. For the task of assigning labels to an image to summarize its contents, many early attempts use segment-level information and try to determine which parts of the images correspond to which labels. Best performing methods use global image similarity and nearest neighbor techniques to transfer labels from training images to test images. However, global methods cannot localize the labels in the images, unlike segment-level methods. Also, they cannot take advantage of training images that are only locally similar to a test image. We propose several ways to combine recent image-level and segment-level techniques to predict both image and segment labels jointly. We cast our experimental study in an unified framework for both image-level and segment-level annotation tasks. On three challenging datasets, our joint prediction of image and segment labels outperforms either prediction alone on both tasks. This confirms that the two levels offer complementary information