In the invited lecture at the international conference we presented our results on EpCAM, specifically that it does not function as a cell adhesion molecule but rather as a signaling receptor for a yet unidentified ligand (binding to the hydrophobic pocket within EpCAM's extracellular part) which affects proteolytic processing of EpCAM and consequently proliferation-enhancing signaling.
B.04 Guest lecture
COBISS.SI-ID: 1537886915In the lecture at the international meeting we presented a complex approach we took for the analysis of EpCAM's cell adhesion function using various methods: SAXS, chemical crosslinking coupled to mass spectrometry, bead aggreggation assay, and FLIM-FRET. We demonstrated that EpCAM does not facilitate cell-cell adhesion via formation of homo-oligomeric units.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 1537560259EpCAM oligomerization has long been postulated as the underlying mechanism of protein's role in cell-cell adhesion. Cell-cell adhesion unit was believed to be a trans-tetramer, which is formed at the areas of cell-cell contact by two cis-dimers on the opposing cells. Despite the recent crystal structure of EpCAM's ectodomain cis-dimer, structural data on trans-tetramers was almost non existent. During the course of this PhD, we focused on structural and biochemical characterisation of trans-tetramer. We believed this information would provide novel insights on how is EpCAM oligomerization regulated and enable us to describe the function of individual oligomeric states in physiological processes in which EpCAM is involved. Using four complementary methods (SAXS, XL-MS, bead aggregation assays and FLIM-FRET), we managed provide a comprehensive overview on EpCAM oligomerization both in vitro and in vivo. Our results clearly show, EpCAM in fact does not form trans-tetramers and thus can't function as a homophilic cell-cell adhesion molecule as previously accepted for more than 20 years. During our research we also established and optimised experimental methods, which will help us characterise complexes of EpCAM with its interacting partners in the future.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 1538058691Project members are also mentors at undergraduate and postgraduate study programs of Biochemistry at FKKT UL. During the course of this project, several students worked on this topic as a part of their diploma or masters thesis: Master thesis: ŽAGAR, Tomaž. Characterization of oligomeric states of EpCAM protein in vivo: Master thesis. Ljubljana: [T. Žagar], 2018. [COBISS.SI-ID 1537914819] KOSTANJEVEC, Mojca. Reconstruction of EpCAM protein in phospholipide bilayer: Master thesis. Ljubljana: [M. Kostanjevec], 2018. [COBISS.SI-ID 1538027715] PRINČIČ, Griša Grigorij. Design and synthesis of EpCAM specific small molecules: Master thesis. Ljubljana: [G. Prinčič], 2016. VI, 51 str., ilustr. [COBISS.SI-ID 1537150147] KOZAK, Eva Lucija. Characterization of EpCAM interaction with claudin-7: Master thesis. Ljubljana: [E. L. Kozak], 2016. [COBISS.SI-ID 1537276611] ŽUŽEK, Barbara. Characterization of the interaction between ?-actinin 4 and the cytosolic part EpCAM and Trop2: Master thesis. Ljubljana: [B. Žužek], 2016. [COBISS.SI-ID 1537289667] Diploma: DEJANOVIĆ, Luka. Design and preparation of various forms of intracellular part of EpCAM protein: Diploma. Ljubljana: [L. Dejanović], 2017. [COBISS.SI-ID 1537499587] MORAVEC, Živa. Preparation of chimeric dimerization forms of EpCAM protein: Diploma: univerzitetni študijski program 1. stopnje Biokemija. Ljubljana: [Ž. Moravec], 2017. [COBISS.SI-ID 1537469635] KURET, Klara. Preparation of recombinant ß-catenin and FHL and optimization of their production process: Diploma: univerzitetni študijski program 1. stopnje Biokemija. Ljubljana: [K. Kuret], 2017. [COBISS.SI-ID 1537499075] ŽAGAR, Tomaž. Preparation of monomeric mutants of protein EpCAM: Diploma. Ljubljana: [T. Žagar], 2016. [COBISS.SI-ID 1537115843] KEJŽAR, Nejc. Structural characteristics of clavdin oligomerization: Diploma: univerzitetni študijski program 1. stopnje Biokemija. Ljubljana: [N. Kejžar], 2018. [COBISS.SI-ID 1537825475] HOČEVAR, Jošt. The role of the hydrophobic pocket of EpCAM and Trop2 in signaling via regulated intramembranous proteolysis: Diploma: univerzitetni študijski program 1. stopnje Biokemija. Ljubljana: [J. Hočevar], 2018. [COBISS.SI-ID 1537865923]
D.10 Educational activities
COBISS.SI-ID: 1537914819