Open Access. Powered by Scholars. Published by Universities.®

Biochemistry, Biophysics, and Structural Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 5 of 5

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Evolution Of Molecular Function In Mammalian Neurons, Chantal Francis Dec 2011

Evolution Of Molecular Function In Mammalian Neurons, Chantal Francis

Publicly Accessible Penn Dissertations

A common question in neuroscience is what forms the neurological basis of the variety of behaviors in mammals. While many studies have compared mammalian anatomy and evolution, few have investigated the physiologic functions of individual neurons in a comparative manner. Neurons’ ability to modify their features in response to stimuli, known as synaptic plasticity, is fundamental for learning and memory. A key feature of synaptic plasticity involves delivering mRNA to distinct domains where they are locally translated. Regulatory coordination of these events is critical for synaptogenesis and synaptic plasticity as defects in these processes can lead to neurological diseases. In ...


Investigating Trna Release From The Bacterial Ribosome, Ian S. Farrell Aug 2011

Investigating Trna Release From The Bacterial Ribosome, Ian S. Farrell

Publicly Accessible Penn Dissertations

Translation of mRNA into proteins is integral in all living organisms, and takes place on the ribosome. In recent years, the X-ray crystal structures of biologically relevant ribosome complexes came into light, and the advance of kinetic studies was soon to follow, leading to a better understanding of the general ribosomal mechanism. However, there still remains some ambiguity in certain ribosome functions.

Ribosomal protein L1 initially became relevant in the early 1980s when it was determined that ribosomes lacking L1 showed a decreased capacity for in vitro protein synthesis. Later, it was shown that the L1-stalk is a highly mobile ...


Mechanism Of Cyclin D1-Dependent Genomic Instability And Neoplastic Transformation, Laura Pontano Vaites Aug 2011

Mechanism Of Cyclin D1-Dependent Genomic Instability And Neoplastic Transformation, Laura Pontano Vaites

Publicly Accessible Penn Dissertations

Regulation of cyclin D1-dependent kinase activity is essential for cell cycle progression and DNA replication fidelity. Critically, impaired cyclin D1 phosphorylation and ubiquitin-mediated proteolysis following the G1/S transition drives neoplastic growth, suggesting that posttranslational regulation is required for cell homeostasis. Elucidation of mechanisms facilitating S-phase cyclin D1 accumulation and novel functions of nuclear cyclin D1/CDK4 kinase is critical for understanding the role of cyclin D1 in tumorigenesis. The work presented herein demonstrates that accelerated, Fbx4-dependent cyclin D1 degradation following S-phase DNA damage is essential to maintain genome stability. Furthermore, Fbx4 functions as a bona fide tumor suppressor, as ...


Role And Regulation Of Myosin Iia In Natural Killer Cell Cytotoxicity, Keri Sanborn Aug 2011

Role And Regulation Of Myosin Iia In Natural Killer Cell Cytotoxicity, Keri Sanborn

Publicly Accessible Penn Dissertations

Natural killer (NK) cells are lymphocytes of the innate immune system that provide defense by directing their cytotoxic activity against virally infected and tumorigenic cells. Target cell lysis requires directed secretion of lytic granule contents, including pore-forming perforin and apoptosis-inducing granzymes, at the contact site. During the formation of a mature immunological synapse (IS) with a target cell, an NK cell polymerizes filamentous actin (F-actin) at the contact site, which may serve as a barrier to secretion of lytic granules for cytotoxicity. An actin-based motor protein, nonmuscle myosin IIA, has been demonstrated to be required for NK cell cytotoxic activity ...


Decoding Cytochrome C Oxidase Biogenesis: New Insights Into Copper Trafficking, Nursel Seda Ekici Jan 2011

Decoding Cytochrome C Oxidase Biogenesis: New Insights Into Copper Trafficking, Nursel Seda Ekici

Publicly Accessible Penn Dissertations

Acquisition, delivery and incorporation of metals to their respective metalloproteins are important cellular processes. These processes are tightly controlled so that cells are not exposed to free metal concentrations that would lead to harmful oxidative damages. Cytochrome c oxidases (Cox) are among these metalloproteins whose assembly and activity involves incorporation of Cu cofactor into their catalytic subunits in addition to the maturation of other subunits. In this study, we focused on the pathways of acquisition of Cu by the facultative phototroph Rhodobacter capsulatus for incorporation into the heme–Cu binuclear center of its cbb3–type Cox (cbb3–Cox ...