Identification of transglutaminase 2 substrates in HUVEC cells

Abstract

This thesis investigates the identification of Transglutaminase 2 (TG2) substrate proteins in human umbilical vein endothelial cells (HUVECs). Using biotin-based substrate labeling, affinity purification, and LC-MS/MS analysis, the study aimed to identify both glutamine-donor and lysine-donor TG2 substrates. Eight glutamine-donor substrate proteins were successfully identified, including proteins involved in glycolysis, cytoskeletal organization, and cellular structure. Comparison with existing databases confirmed most of these proteins as known TG2 substrates, while pyruvate kinase (PKM) emerged as a potential novel substrate in HUVEC cells. In parallel, lysine-donor substrate labeling and enrichment were successfully established, providing the basis for ongoing mass spectrometry analysis. The findings contribute to a better understanding of TG2 function in endothelial biology and its potential relevance in cardiovascular disease, cancer, and angiogenesis-related processes.