Desminin çekirdeğe taşınımının potansiyel mekanizmalarının araştırılması

Abstract

Kural Mangıt E., Investigation of Potential Mechanisms for Nuclear Transport of Desmin. Hacettepe University, Graduate School of Health Sciences, Ph.D. Thesis in Medical Biology, Ankara, 2024. Studies have shown that cytoskeletal proteins, which are primarily located at the cytoplasm, can be transported to the nucleus and play significant roles within the nucleus. The nucleocytoplasmic transport occurs with different mechanisms through the nuclear pore complex. Proteins can be transported through the nuclear pore complex via a specific signal sequence on their surface (karyopherin-dependent transport) or by directly interacting with elements of the nuclear pore complex through structural changes (karyopherin-independent transport). Desmin is an intermediate filament protein specific to muscle cells that mostly have structural functions. In silico analyzes showed that desmin has special signal sequences that ara necessary for nucleocytoplasmic transport. In addition, desmin is an amphiphilic protein that interacts with proteins responsible for transport in the nuclear pore complex. Within the scope of this thesis, the nucleocytoplasic transport mechanisms of desmin were investigated. Mutant expression vectors created by removing the potential signal sequences on desmin were transfected into the human and mouse skeletal muscle cells, and the signal sequences responsible for nucleocytoplasmic transport were proven to be functional via confocal imaging. Subsequently, the karyopherin-dependent transport pathway was inhibited by a small molecule (ivermectin), and it was shown that desmin can be transported into the nucleus in a karyopherin-dependent manner. The findings of nuclear import assay did not substantiate a preference for a karyopherin independent mechanism for the translocation of desmin into the nucleus. However, hydrophobicity measurements have shown that desmin can undergo conformational changes in order to adapt hydrophobic environments, such as nuclear pore complex. In conclusion, the transport mechanisms of desmin have been investigated. Illuminating these mechanisms is not only important for elucidating the nuclear functions of desmin but also for developing novel treatment targets related to diseases.