Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Elucidation of Lysosomal Cathepsin a in the Regulation of Autophagy(01. Izmir Institute of Technology, 2023) Seyrantepe, Volkan; Seyrantepe, Volkan; 04.03. Department of Molecular Biology and Genetics; 04. Faculty of Science; 01. Izmir Institute of TechnologyLysosomal Cathepsin A (CathA) is a multifunctional enzyme with independent catalytic and protective functions. It has a serine carboxypeptidase activity in acidic pH conditions for the degradation of short bioactive peptides that are vasoactive peptides including endothelin-1, angiotensin-I, bradykinin and neuropeptides including oxytocin and substance P. Lysosomal CathA enzyme also forms a lysosomal multienzyme complex (LMC) with α-neuraminidase (Neu1) and ß-Galactosidase (ß-Gal) enzymes to protect them from hydrolytic degradation in lysosomes and due to its protective function. Genetic defects in the lysosomal CathA enzyme causes a rare lysosomal storage disorder, Galactosialidosis (OMIM #256540), with secondary deficiencies of Neu1 and ß-Gal enzymes. Catalytically inactive Cathepsin A knock-in mouse model, CathAS190A has point mutation in the active catalytic site which serine was replace with alanine amino acid. Accumulation of short bioactive peptides has been reported in previous studies in different tissues of the CathAS190A mouse model. In this thesis study, investigation the role of the lysosomal CathA enzyme in the regulation of autophagic flux in neuroglia and fibroblast cell lines derived from CathAS190A mice was aimed. For this aim; RT-PCR, Western Blot and Immunocytochemical analyses were for performed for autophagy markers. Thesis study results have exhibited that catalytically deficient CathA causes the impairment in autophagic machinery with secondary accumulation of autophagic substrates and alterations in the expression of the autophagy marker genes. Accumulation of the short bioactive peptides due to the catalytically inactive CathA enzyme may be related to to impaired autophagic flux. Autophagy-inducing Rapamycin and Starvation treatment conditions may restore the impaired autophagic flux due to catalytically inactive CathA enzyme with the clearance of accumulation of secondary autophagic substrates.Master Thesis Investigating the Regulatory Role of Lysosomal Protein Cathepsin a in Vasoactive Peptide Biology(Izmir Institute of Technology, 2016) Çalhan, Osman Yipkin; Seyrantepe, Volkan; Seyrantepe, Volkan; 04.03. Department of Molecular Biology and Genetics; 04. Faculty of Science; 01. Izmir Institute of TechnologyThe lysosomal carboxypeptidase A, Cathepsin A (CathA), is a serine protease with distinct functions. CathA protects sialidase Neu1 and β- galactosidase against proteolytic degradation by forming a multi-enzyme complex and was shown to be activating sialidase Neu1. Mutations in the CathA gene cause the lysosomal storage disease galactosialidosis. Patients with galactosialidosis are characterized with a broad range of clinical phenotypes, involving growth retardation, neurological deterioration and accumulation of vasoactive peptide, endothelin-1 in the brain. CathA is also a multi-catalytic enzyme with deamidase and esterase activity at neutral pH, and carboxypeptidase activity at acidic pH. Previous investigations have presented that CathA has specific enzyme activity against vasoactive and neuropeptides, including endothelin-1, oxytocin and substance P. A generated mouse model with inactive CathA enzyme activity (CathAS190A) showed significantly increased level of precursor endothelin-1 vasoactive peptide with increased arterial blood pressure. The aim of this study was to ascertain the regulatory role of CathA against other vasoactive peptide precursors such as oxytocin, endothelin-1 and substance P in vivo. In addition to the regulatory role of the enzyme, CathA’s involvement in learning ability, long term memory and motor cortex functioning was elucidated. Our results showed that CathA has a regulatory role on endothelin-1 and oxytocin peptides’ degradation, which is the reason of the increased accumulation in the brain hippocampus region for CathAS190A. Memory based Morris’ water maze and passive avoidance tests illustrated that CathAS190A animals had lower scores than control littermates, which let us to speculate that CathA may play significant role in memory consolidation and learning ability through its regulatory role on vasoactive peptide biology.