BEGIN:VCALENDAR VERSION:2.0 PRODID:Icfo X-PUBLISHED-TTL:P1W BEGIN:VEVENT UID:69d255ab65080 DTSTART:20230428T090000Z SEQUENCE:0 TRANSP:OPAQUE LOCATION:Auditorium SUMMARY:ICFO | NICOLÁS MATEOS ESTÉVEZ CLASS:PUBLIC DESCRIPTION: \;\nThe spatiotemporal organisation and compartmentalisati on of molecules in living cells is crucial to regulate cell function. Dysr egulation in how molecules dynamically explore their environment and inter act with other molecules can lead to disease and death. Therefore\, unders tanding the nature of these dynamic interactions is pivotal in cell biolog y studies. Fluorescence light microscopy is the preferred approach to perf orm the necessary biophysical studies and it has led to major findings in the field. Nevertheless\, spatial and temporal studies are typically condu cted separately due to technical limitations. Moreover\, quantitative imag ing and novel analysis toolboxes are required to address new questions in the field. The aim of this thesis is three-fold: (1) develop and implement novel algorithms to analyse super-resolution microscopy data to study the spatial organisation of a variety of proteins at the plasma membrane of c ells\; (2) develop a novel methodology to study the spatiotemporal organis ation of receptors at the plasma membrane of cells based on high-density s ingle particle tracking\; and (3) apply our novel methodology in a multi-c olour scheme to study the compartmentalisation of DC-SIGN and its multi-co mponent interactions with CD44 and Galectin 9 during viral engagement.\nIn Chapter 1\, we overview how cells are compartmentalised from the intra-ce llular organisation to how the cell membrane is compartmentalised by multi ple organisers acting most probably in synergy. Also\, in Chapter 1\, we r eview the main fluorescence microscopy techniques used in the field of cel l biology to study the spatiotemporal organisation of molecules in cells. In Chapter 2\, we present the analyses that we have performed to super-res olution microscopy techniques such as stimulated emission depletion (STED) and stochastic optical reconstruction microscopy (STORM). We have used th ese techniques to elucidate the spatial organisation of proteins at the pl asma membrane such as Siglec-1\, integrins or PRL-3. We have implemented s tate-of-the-art algorithms into our analysis workflow to resolve the biolo gical inquiries of our research. In Chapter 3\, we change gears and presen t our novel methodology to analyse high-density single particle tracking\, which consists on generating high-density maps (HiDenMaps). In this chapt er\, we specify the technical requirements to obtain a faithful representa tion on how molecules explore space. In Chapter 4\, we study CD44 which is a transmembrane protein extremely interesting because it can interact wit h the underlying cortical actin and the extracellular milieu. Moreover\, i t is thought to act as a key actor in the spatiotemporal compartmentalisat ion of the plasma membrane for third receptors that do not interact direct ly with actin. In this Chapter\, we have used HiDenMaps to elucidate the h ierarchical organisation of CD44 at the plasma membrane of living cells. I n Chapter 5\, we present a palette of analysis tools to further quantify t he patterns revealed by HiDenMaps and resolve the temporal dynamics of the se patterns. Moreover\, our work reveals a multi-scale organisation of CD4 4 ranging from fast single molecules dynamics with a mesoscale dynamic com partmentalisation. In Chapter 6\, we present a functional study on viral c apture by DC-SIGN in immature dendritic cells. We extended our HiDenMap me thodology to a multi-colour scheme to study the multi-component interactio ns of DC-SIGN with CD44 and Galectin 9 during viral engagement. Importantl y\, we demonstrate the existence of DC-SIGN/CD44/Galectin 9 tripartite pre -docking platform that enhances the successful engagement of HIV-1 and SAR S-CoV-2 virus-like particles in immature dendritic cells. Finally\, in Cha pter 7 we summarise the main results of this thesis and highlight future d irections of our research.\n \;\nThesis Director: Prof Dr. Marí\ ;a Garcí\;a Parajo &\; Dr. Juan Torreñ\;o Piñ\;a DTSTAMP:20260405T122931Z END:VEVENT END:VCALENDAR