Proteins and mechanisms involved in endosomal sorting of the epidermal growth factor receptor

Signaling from growth factor receptors is tightly regulated. Failure of this regulation can lead to overstimulation of growth, proliferation and differentiation, and is often observed in cancer. The epidermal growth factor receptor (EGFR) is desensitized by internalization and degradation in lysosomes. Internalization takes place rapidly upon ligand induced activation, whereas degradation depends on retained ligand binding and subsequent sorting to inner vesicles on multivesicular bodies (MVBs). Using electron-microscopy, confocal immunofluorescence microscopy and standard molecular biology techniques, we have investigated endocytosis and endosomal sorting of EGFR. Endocytosis of the activated EGFR is believed to depend on ubiquitination of the receptor. Ubiquitination depends on the ubiquitin ligase Cbl, and we show that the direct interaction between EGFR and Cbl at the phosphorylated tyrosine residue 1045 (pY1045) of the EGFR is sufficient for endocytosis of the EGFR, but not sufficient for sorting to MVBs and degradation. On endosomes, different membrane domains are involved in sorting of the endocytosed EGFR, and we found that two different electron dense coats are involved, one coat containing clathrin and Hrs, and another coat devoid of clathrin and Hrs. Hrs is involved in sorting of ubiquitinated receptors for degradation, and we further found that the ubiquitination induced by direct interaction between EGFR and Cbl at the pY1045 of the EGFR is necessary for co-localization between the EGFR and Hrs. Finally, we found the non-receptor tyrosine kinase Ack1, which is often over-expressed in cancer, to be involved in EGFR endocytosis, most likely at the level of endosomal sorting. Ack1 colocalized with the EGFR on early endosomes and overexpression of Ack1 retained the EGFR on the limiting membrane of early endosomes and inhibited sorting of the EGFR to inner vesicles of MVBs

Developing and Testing Digital Twins for Vehicle Collision Prediction: A Machine Learning and Genetic Search Algorithm Approach

This thesis focuses on developing a digital twin which can predict and avoid collisions. The digital twin does this by using different machine learning models that are trained on data from the SVL Simulator. By harnessing the power of machine learning, the digital twin demonstrates promising abilities in collision prediction and prevention. Additionally, a genetic search algorithm is developed to generate specialized testing data, enabling comprehensive evaluation of the digital twin's performance. The central contribution of this research lies in exploring the viability of utilizing test data that is generated by a genetic search algorithm to evaluate the performance of the digital twin. By employing the genetic search algorithm to generate data resembling real collision scenarios, classified as collisions, an interesting evaluation framework is established. Through the evaluation process, which involves analyzing the number of accurately classified collisions by the digital twin, insights are gained into the model's effectiveness in predicting collisions. This contributes to the ongoing efforts in enhancing the accuracy of collision prediction systems, ultimately leading to improved safety measures in autonomous driving and intelligent transportation systems

Anvendelse av Lean Startup i boligutvikling

Masteroppgave økonomi og administrasjon - Universitetet i Agder 2016Masteroppgaven har som formål å undersøke hvorvidt Lean Startup-metodikken kan anvendes innenfor boligutvikling. Byggebransjen er kritisert for å være lite innovativ og for å ha behov for et større fokus på samhandling med kunden (Bygballe, 2015). Lean Startup er en iterativ arbeidsmetodikk for produkt- og forretningsutvikling som vi tror kan forbedre den nåværende boligutviklingsprosessen. Lean Startup-metodikken søker å optimalisere ressursbruken i produktog forretningsutvikling, samt redusere faren for å lansere et produkt det ikke er et marked for. Studien adresserer tre forskningsspørsmål. Det undersøkes hvordan boligutvikling gjøres i Norge i dag. Videre undersøkes det om Lean Startup kan anvendes innenfor boligutviklingsprosessen og i tilfelle hvordan det kan anvendes. Det undersøker også hvilke fordeler og utfordringer anvendelse av Lean Startup vil medføre i boligutviklingsprosessen. Skanska Norge benyttes som case i oppgaven. Funnene i studien er gjort på bakgrunn av en todelt kvalitativ tilnærming, som bestod av individuelle intervjuer og en workshop. Det konkluderes med at det er mulig å anvende Lean Startup-metodikken innenfor boligutvikling. Basert på funnene presenteres en modell for anvendelse av Lean Startup innenfor boligutvikling. Modellen består av fire trinn, hvor det itereres innenfor hvert trinn til utvikleren har oppnådd tilfredsstillende læring om kunden og markedet. I trinn en testes det hvorvidt tomten er attraktiv ved å benytte en annonse med bilder av tomten. I trinn to verifiseres det at konsept og uteområder treffer kundene i prosjektet. I trinn tre testes og utvikles modeller og plantegninger for boligene. I trinn fire legges boligene ut for salg og mindre tilpasninger gjøres etter kundenes ønsker. Underveis i utviklingen bekreftes etterspørsel ved at potensielle kunder registrerer seg på interessentlister eller reserverer bolig mot et refunderbart beløp. Vi finner at anvendelse av Lean Startup-metodikken i boligutvikling vil kunne være tid- og ressursbesparende. Det vil også sørge for at man i større grad kan levere boliger som har verdi for kundene. Gevinsten av å benytte Lean Startup vil være størst i områder hvor markedsgrunnlaget er lite og usikkert, men vi finner også fordeler ved å benytte metodikken i trygge markeder

Entry by multiple picornaviruses is dependent on a pathway that includes TNK2, WASL, and NCK1

Comprehensive knowledge of the host factors required for picornavirus infection would facilitate antiviral development. Here we demonstrate roles for three human genes

Molecular constituents of the extracellular matrix in rat liver mounting a hepatic progenitor cell response for tissue repair

BACKGROUND: Tissue repair in the adult mammalian liver occurs in two distinct processes, referred to as the first and second tiers of defense. We undertook to characterize the changes in molecular constituents of the extracellular matrix when hepatic progenitor cells (HPCs) respond in a second tier of defense to liver injury. RESULTS: We used transcriptional profiling on rat livers responding by a first tier (surgical removal of 70% of the liver mass (PHx protocol)) and a second tier (70% hepatectomy combined with exposure to 2-acetylaminofluorene (AAF/PHx protocol)) of defense to liver injury and compared the transcriptional signatures in untreated rat liver (control) with those from livers of day 1, day 5 and day 9 post hepatectomy in both protocols. Numerous transcripts encoding specific subunits of collagens, laminins, integrins, and various other extracellular matrix structural components were differentially up- or down-modulated (P < 0.01). The levels of a number of transcripts were significantly up-modulated, mainly in the second tier of defense (Agrn, Bgn, Fbn1, Col4a1, Col8a1, Col9a3, Lama5, Lamb1, Lamb2, Itga4, Igtb2, Itgb4, Itgb6, Nid2), and their signal intensities showed a strong or very strong correlation with Krt1-19, a well-established marker of a ductular/HPC reaction. Furthermore, a significant up-modulation and very strong correlation between the transcriptional profiles of Krt1-19 and St14 encoding matriptase, a component of a novel protease system, was found in the second tier of defense. Real-time PCR confirmed the modulation of St14 transcript levels and strong correlation to Krt-19 and also showed a significant up-modulation and strong correlation to Spint1 encoding HAI-1, a cognate inhibitor of matriptase. Immunodetection and three-dimensional reconstructions showed that laminin, Collagen1a1, agrin and nidogen1 surrounded bile ducts, proliferating cholangiocytes, and HPCs in ductular reactions regardless of the nature of defense. Similarly, matriptase and HAI-1 were expressed in cholangiocytes regardless of the tier of defense, but in the second tier of defense, a subpopulation of HPCs in ductular reactions co-expressed HAI-1 and the fetal hepatocyte marker Dlk1. CONCLUSION: Transcriptional profiling and immunodetection, including three-dimensional reconstruction, generated a detailed overview of the extracellular matrix constituents expressed in a second tier of defense to liver injury

Differential Effects of EGFR Ligands on Endocytic Sorting of the Receptor

Endocytic downregulation is a pivotal mechanism turning off signalling from the EGF receptor (EGFR). It is well established that whereas EGF binding leads to lysosomal degradation of EGFR, transforming growth factor (TGF)-α causes receptor recycling. TGF-α therefore leads to continuous signalling and is a more potent mitogen than EGF. In addition to EGF and TGF-α, five EGFR ligands have been identified. Although many of these ligands are upregulated in cancers, very little is known about their effect on EGFR trafficking

The lay-up decision in practice : how offshore supply shipowners respond to lower demand

The purpose of this thesis is to improve the understanding of how offshore supply shipowners adapt to lower demand by putting ships in lay-up. We have examined how day rates affect lay-up levels, and sought to explain other factors than day rates that might impact the lay-up decision. We have also looked at how specific vessel characteristics impact the likelihood that a given vessel will be laid up. We have used both a qualitative and an empirical approach in our research. In the qualitative part, we have interviewed seven Norwegian offshore supply shipowners that operate Platform Supply Vessels (PSV) and/or Anchor Handling Tug Supply (AHTS) vessels in the North Sea. We have found that in addition to using lay-up to reduce costs, the shipowners see the opportunity to reduce supply as a main motivation for laying up vessels. They achieve this by coordinating lay-up levels and thus engage in tacit collusion. Furthermore, we have found that the attractiveness of lay-up depends on the market outlook, the opportunity to scrap or sell vessels, startup costs for new vessels, vessel deterioration when in lay-up, and the ability to keep employees and competence in the company. The qualitative part of our research enabled us to formulate some hypotheses that we tested empirically using fleet statistics and day rates from the North Sea region. Using OLS, we found that day rates are negatively correlated with lay-up levels, but that there might be a time lag in how a reduction in day rates leads to an increase in laid up vessels. Using logistic regression, we found that vessel age had some negative correlation with layup levels, though the correlation was not strong. High capacity as measured by clear deck area for PSVs had a significant, negative correlation with the likelihood of lay-up. Bollard pull had a significant, negative correlation with the likelihood of lay-up for AHTSs.nhhma

Case-alternation with Japanese adjectives: A cognitive transitive perspective

The aim of this thesis is to explain the observed case-alternation occurring with the three Japanese predicates suki 'like', kirai 'dislike' and hoshii 'want' from a Cognitive Linguistic standpoint. These three predicates alternately appear in a construction in which the second nominal receives nominative and accusative marking, with the nominative considered to be the 'standard'. The goal of this thesis is to assess whether the observed 'non-standard' accusative marking on these predicates‟ second nominals can be accounted for by appealing to the semantic nuances of the sentences in which they occur. More specifically, the hypothesis tested is that the case-alternation can be explained by the predicate-containing sentences taking on an interpretation more closely resembling the experiential category of 'prototypical transitive event' The findings which emerged from analyzing the various materials (previous research, language corpora, speaker judgments) seem to provide a relatively strong case for the validity of this hypothesis. In particular, transitivity-related factors such as 'event-likeness', 'object affectedness', 'dynamicity', 'volition' and 'object-likeness' had significant explanatory value in accounting for the use of accusative marking on the predicates' second nominals, although the observed effect was more apparent for the suki and kirai predicates. The correlations between the presence of these factors and accusative marking were stronger than those found for previously hypothesized causes. Additionally, the empirical analyses hinted at the existence of a 'semantic split', in which the predicates with accusatively marked second nominals express 'feelings', while those with traditional nominatively marked second nominals express 'preferences'. This seems to suggest that the alternation can, to a large extent, be accounted for by a difference in the meaning that the utterer wishes to convey. The relative success of the hypothesis in accounting for the phenomenon at hand has several important implications. Firstly, it shows the validity of the Cognitive Linguistics approach in accounting for empirical language data, giving particular weight to Ronald W. Langacker‟s definition of transitivity. Furthermore, I believe that this thesis has led to insights related to the use of accusative marking, both in conjunction with the suki, kirai, and hoshii predicates, and in general. These observations may contribute towards developing a new way of instructing non-native speakers to use such marking in a more 'natural' way