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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6
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Publication Open Access Crosstalk between autophagy and DNA repair systems(TÜBİTAK, 2021) Demirbağ Sarıkaya, Sinem; Çakır, Hatice; Gözüaçık, Devrim; Akkoç, Yunus; Faculty Member; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); School of Medicine; 40248; N/AAutophagy and DNA repair are two essential biological mechanisms that maintain cellular homeostasis. Impairment of these mechanisms was associated with several pathologies such as premature aging, neurodegenerative diseases, and cancer. Intrinsic or extrinsic stress stimuli (e.g., reactive oxygen species or ionizing radiation) cause DNA damage. As a biological stress response, autophagy is activated following insults that threaten DNA integrity. Hence, in collaboration with DNA damage repair and response mechanisms, autophagy contributes to the maintenance of genomic stability and integrity. Yet, connections and interactions between these two systems are not fully understood. In this review article, current status of the associations and crosstalk between autophagy and DNA repair systems is documented and discussed.Publication Open Access CLIC4 and CLIC1 bridge plasma membrane and cortical actin network for a successful cytokinesis(Life Science Alliance LLC, 2020) Department of Molecular Biology and Genetics; Department of Molecular Biology and Genetics; Kagiali, Zeynep Cansu Üretmen; Şanal, Erdem; Değirmenci, Beste Senem; Mollaoğlu, Gürkan; Saner, Nazan; Master Student; Faculty Member; Researcher; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; N/A; N/A; 105301; 227757CLIC4 and CLIC1 are members of the well-conserved chloride intracellular channel proteins (CLICs) structurally related to glutathione-S-transferases. Here, we report new roles of CLICs in cytokinesis. At the onset of cytokinesis, CLIC4 accumulates at the cleavage furrow and later localizes to the midbody in a RhoA-dependent manner. The cell cycle-dependent localization of CLIC4 is abolished when its glutathione S-transferase activity-related residues (C35A and F37D) are mutated. Ezrin, anillin, and ALIX are identified as interaction partners of CLIC4 at the cleavage furrow and midbody. Strikingly, CLIC4 facilitates the activation of ezrin at the cleavage furrow and reciprocally inhibition of ezrin activation diminishes the translocation of CLIC4 to the cleavage furrow. Furthermore, knockouts of CLIC4 and CLIC1 cause abnormal blebbing at the polar cortex and regression of the cleavage furrow at late cytokinesis leading to multinucleated cells. We conclude that CLIC4 and CLIC1 function together with ezrin where they bridge plasma membrane and actin cytoskeleton at the polar cortex and cleavage furrow to promote cortical stability and successful completion of cytokinesis in mammalian cells.Publication Open Access Archaeogenetic analysis of Neolithic sheep from Anatolia suggests a complex demographic history since domestication(Nature Portfolio, 2021) Yurtman, Erinç; Özer, Onur; Yüncü, Eren; Dağtaş, Nihan Dilşad; Koptekin, Dilek; Çakan, Yasin Gökhan; Özkan, Mustafa; Akbaba, Ali; Kaptan, Damla; Atağ, Gözde; Vural, Kıvılcım Başak; Gündem, Can Yümni; Martin, Louise; Kılınç, Gülşah Merve; Ghalichi, Ayshin; Açan, Sinan Can; Yaka, Reyhan; Sağlıcan, Ekin; Lagerholm, Vendela Kempe; Krzewinska, Maja; Gunther, Torsten; Miranda, Pedro Morell; Pişkin, Evangelia; Sevketoğlu, Müge; Bilgin, C. Can; Atakuman, Ciğdem; Erdal, Yılmaz Selim; Sürer, Elif; Altınışık, N. Ezgi; Lenstra, Johannes A.; Yorulmaz, Sevgi; Abazari, Mohammad Foad; Hoseinzadeh, Javad; Baird, Douglas; Bıcakcı, Erhan; Çevik, Özlem; Gerritsen, Fokke; Gotherstrom, Anders; Somel, Mehmet; Togan, İnci; Özer, Füsun; Department of Archeology and History of Art; Department of Archeology and History of Art; Özbal, Rana; Faculty Member; College of Social Sciences and Humanities; 55583Sheep were among the first domesticated animals, but their demographic history is little understood. Here we analyzed nuclear polymorphism and mitochondrial data (mtDNA) from ancient central and west Anatolian sheep dating from Epipaleolithic to late Neolithic, comparatively with modern-day breeds and central Asian Neolithic/Bronze Age sheep (OBI). Analyzing ancient nuclear data, we found that Anatolian Neolithic sheep (ANS) are genetically closest to present-day European breeds relative to Asian breeds, a conclusion supported by mtDNA haplogroup frequencies. In contrast, OBI showed higher genetic affinity to present-day Asian breeds. These results suggest that the east-west genetic structure observed in present-day breeds had already emerged by 6000 BCE, hinting at multiple sheep domestication episodes or early wild introgression in southwest Asia. Furthermore, we found that ANS are genetically distinct from all modern breeds. Our results suggest that European and Anatolian domestic sheep gene pools have been strongly remolded since the Neolithic.Publication Open Access Terminal neuron localization to the upper cortical plate is controlled by the transcription factor NEUROD2(Nature Publishing Group (NPG), 2019) Department of Molecular Biology and Genetics; Department of Physics; Department of Molecular Biology and Genetics; Department of Physics; Akkaya, Cansu; Atak, Dila; Güzelsoy, Gizem; Dunn, Cory David; Dunn, Gülayşe İnce; Kabakçıoğlu, Alkan; Master Student; Faculty Member; Faculty Member; Faculty Member; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; N/A; N/A; 105301; N/A; 49854Excitatory neurons of the mammalian cerebral cortex are organized into six functional layers characterized by unique patterns of connectivity, as well as distinctive physiological and morphological properties. Cortical layers appear after a highly regulated migration process in which cells move from the deeper, proliferative zone toward the superficial layers. Importantly, defects in this radial migration process have been implicated in neurodevelopmental and psychiatric diseases. Here we report that during the final stages of migration, transcription factor Neurogenic Differentiation 2 (Neurod2) contributes to terminal cellular localization within the cortical plate. In mice, in utero knockdown of Neurod2 resulted in reduced numbers of neurons localized to the uppermost region of the developing cortex, also termed the primitive cortical zone. Our ChIP-Seq and RNA-Seq analyses of genes regulated by NEUROD2 in the developing cortex identified a number of key target genes with known roles in Reelin signaling, a critical regulator of neuronal migration. Our focused analysis of regulation of the Reln gene, encoding the extracellular ligand REELIN, uncovered NEUROD2 binding to conserved E-box elements in multiple introns. Furthermore, we demonstrate that knockdown of NEUROD2 in primary cortical neurons resulted in a strong increase in Reln gene expression at the mRNA level, as well as a slight upregulation at the protein level. These data reveal a new role for NEUROD2 during the late stages of neuronal migration, and our analysis of its genomic targets offers new genes with potential roles in cortical lamination.Publication Open Access HMI-PRED 2.0: a biologist-oriented web application for prediction of host-microbe protein-protein interaction by interface mimicry(Oxford University Press (OUP), 2022) Lim, H., Tsai, C.J.; Nussinov, R.; Department of Computer Engineering; Department of Chemical and Biological Engineering; Department of Computer Engineering; Department of Chemical and Biological Engineering; Keskin, Özlem; Gürsoy, Attila; Faculty Member; College of Engineering; 26605; 8745HMI-PRED 2.0 is a publicly available web service for the prediction of host-microbe protein-protein interaction by interface mimicry that is intended to be used without extensive computational experience. A microbial protein structure is screened against a database covering the entire available structural space of complexes of known human proteins.Publication Open Access Cooperative allostery and structural dynamics of streptavidin at cryogenic- and ambient-temperature(Springer Nature, 2022) Yefanov, Oleksandr M.; Barty, Anton; Tolstikova, Alexandra; Ketawala, Gihan K.; Botha, Sabine; Dao, E. Han; Hayes, Brandon; Liang, Mengning; Seaberg, Matthew H.; Hunter, Mark S.; Batyuk, Alexander; Mariani, Valerio; Su, Zhen; Poitevin, Frederic; Yoon, Chun Hong; Kupitz, Christopher; Cohen, Aina; Doukov, Tzanko; Sierra, Raymond G.; Department of Molecular Biology and Genetics; Department of Molecular Biology and Genetics; Dağ, Çağdaş; Ayan, Esra; Yüksel, Büşra; Destan, Ebru; Ertem, Fatma Betül; Yıldırım, Günseli; Eren, Meryem; Demirci, Hasan; Faculty Member; PhD Student; Faculty Member; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; N/A; N/A; N/A; N/A; 307350Ayan et al. report two structures of the protein streptavidin - one at ambient temperature determined using serial femtosecond crystallography and a second one determined at cryogenic temperature. These results provide insights into the structural dynamics of apo streptavidin and reveal a cooperative allostery between monomers for binding to biotin, and the findings are supported by GNM analysis. Multimeric protein assemblies are abundant in nature. Streptavidin is an attractive protein that provides a paradigm system to investigate the intra- and intermolecular interactions of multimeric protein complexes. Also, it offers a versatile tool for biotechnological applications. Here, we present two apo-streptavidin structures, the first one is an ambient temperature Serial Femtosecond X-ray crystal (Apo-SFX) structure at 1.7 angstrom resolution and the second one is a cryogenic crystal structure (Apo-Cryo) at 1.1 angstrom resolution. These structures are mostly in agreement with previous structural data. Combined with computational analysis, these structures provide invaluable information about structural dynamics of apo streptavidin. Collectively, these data further reveal a novel cooperative allostery of streptavidin which binds to substrate via water molecules that provide a polar interaction network and mimics the substrate biotin which displays one of the strongest affinities found in nature.Publication Open Access Proximity mapping of the microtubule plus-end tracking protein SLAIN2 using the BioID approach(TÜBİTAK, 2020) Department of Molecular Biology and Genetics; Department of Molecular Biology and Genetics; Karalar, Elif Nur Fırat; Faculty Member; College of Sciences; 206349The centrosome is the main microtubule-organizing center of animal cells, which plays key roles in critical cellular processes ranging from cell division to cellular signaling. Accordingly, defects in the structure and function of centrosomes cause various human diseases such as cancer and primary microcephaly. To elucidate the molecular defects underlying these diseases, the biogenesis and functions of the centrosomes have to be fully understood. An essential step towards addressing these questions is the identification and functional dissection of the full repertoire of centrosome proteins. Here, we used high-resolution imaging and showed that the microtubule plus-end tracking protein SLAIN2 localizes to the pericentriolar material at the proximal end of centrioles. To gain insight into its cellular functions and mechanisms, we applied in vivo proximity-dependent biotin identification to SLAIN2 and generated its proximity interaction map. Gene ontology analysis of the SLAIN2 interactome revealed extensive interactions with centriole duplication, ciliogenesis, and microtubule-associated proteins, including previously characterized and uncharacterized interactions. Collectively, our results define SLAIN2 as a component of pericentriolar material and provide an important resource for future studies aimed at elucidating SLAIN2 functions at the centrosome.