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Full-Text Articles in Life Sciences

Motor Protein Regulation In Mammalian Mitosis, Barbara Mann Jul 2018

Motor Protein Regulation In Mammalian Mitosis, Barbara Mann

Doctoral Dissertations

Developing and maintaining a multicellular organism relies on the fundamental biological process of cell division, which ensures that genetic material is equally segregated between daughter cells. During mitosis, cells completely rearrange their cytoskeleton into a bipolar spindle through the concerted efforts of microtubules, motor proteins, and microtubule-associated proteins, which cells must regulate spatially and temporally to prevent errors such as chromosomal missegregation: a major cause of cancer. Although the mitotic spindle is a validated target for chemotherapy drug resistance and redundant pathways have highlighted the need for new targets. It is therefore important to understand how proteins that help build ...


Characterizing The Inhibition Of Katanin Using Tubulin Carboxy-Terminal Tail Constructs, Corey E. Reed Nov 2016

Characterizing The Inhibition Of Katanin Using Tubulin Carboxy-Terminal Tail Constructs, Corey E. Reed

Masters Theses

Understanding how the cellular cytoskeleton is maintained and regulated is important to elucidate the functions of many structures such as the mitotic spindle, cilia and flagella. Katanin p60, microtubule-severing enzymes from the ATPase associated with cellular activities (AAA+) family, has previously been shown in our lab to be inhibited by free tubulin as well as α- and β-tubulin carboxy-terminal tail (CTT) constructs. Here we investigate the inhibition ability of several different tubulin CTT sequences. We quantify the effect of the addition of these constructs on the severing and binding activity of katanin. We find that some constructs inhibit katanin better ...


Dynamics Of Microtubule Networks With Antiparallel Crosslinkers, Kasimira T. Stanhope Jul 2016

Dynamics Of Microtubule Networks With Antiparallel Crosslinkers, Kasimira T. Stanhope

Masters Theses

Microtubules are the most rigid element of the cytoskeleton. They are responsible for the structure of cells and make up the tracks for intracellular cargo transport. Interactions between microtubules, motor proteins, and microtubule-associated proteins drive important mechanisms in the cell, such as cell division, cell motility, cell homeostasis, and cell signaling. I seek to understand how such complex, energy-consuming non-equilibrium biological networks self-organize by studying in vitro microtubules bundled by microtubule-associated protein 65 (MAP65), in kinesin-1 gliding assays. I found that large networks can break into smaller, cell-like networks that can mimic types of cell motility. Dynamics of these networks ...


Studies Of Kinetochore Mechanobiology In Drosophila, Stuart Cane Mar 2016

Studies Of Kinetochore Mechanobiology In Drosophila, Stuart Cane

Doctoral Dissertations

Kinetochores are large multiprotein structures through which chromosomes engage with the microtubules of the mitotic spindle. All kinetochore pairs must ultimately adopt a bioriented configuration, with their associated sister chromatids linked to opposite spindle poles and poised to segregate equally between two daughter cells. Erroneous, non-bioriented attachments that are left uncorrected lead to chromosome mis-segregation, producing aneuploid daughter cells with unequal numbers of chromosomes. Before anaphase onset, bioriented attachments are selectively stabilized whereas non-bioriented attachments remain unstable and are eliminated. This error correction process relies heavily on the extent of outer kinetochore phosphorylation by an Aurora B kinase activity centered ...


Biophysical Characterization Of Katanin’S Regulation Of Microtubules, Megan E. Bailey Nov 2015

Biophysical Characterization Of Katanin’S Regulation Of Microtubules, Megan E. Bailey

Doctoral Dissertations

Microtubules, as an essential part of the cytoskeleton, require proper function as well as correct spatial and temporal localization. In order to achieve correct organization, microtubule-associated proteins (MAPs) regulate microtubule dynamics. Katanin, a known microtubule-severing enzyme from the AAA family of proteins, plays a role in regulating microtubules, but the mechanisms of microtubule control and the mechanism of severing activity remain to be elucidated.

In the following studies I examine mechanisms of katanin-based regulation of microtubule dynamics using a single molecule biophysics approach. I use this simplified in vitro approach to change specific parameters to investigate how katanin targets microtubules ...


Functional Analysis Of Moss Class Viii Myosin And Its Role In Plant Cell Division, Shu-Zon Wu Aug 2014

Functional Analysis Of Moss Class Viii Myosin And Its Role In Plant Cell Division, Shu-Zon Wu

Doctoral Dissertations

The moss Physcomitrella patens is a great model system for studying plant gene function using reverse genetic approaches. It undergoes efficient gene-targeting by homologous recombination, allowing the generation of specific gene knockout and tagging a gene at its endogenous locus. Additionally, RNAi is quite effective in P. patens, providing an effective tool for rapid gene silencing and phenotypic characterization. Taking advantage of these features, this dissertation described the establishment of a system to perform an unbiased gene-by-gene RNAi assay to screen for tip growth phenotypes in P. patens. A small set of RNAi constructs were tested, within them one gene ...


Biophysical Studies Of Axonal Transport, Leslie Cyle Conway Apr 2014

Biophysical Studies Of Axonal Transport, Leslie Cyle Conway

Doctoral Dissertations

Intracellular transport provides a mechanism by which cellular material, such as organelles, vesicles, and protein, can be actively transported throughout the cell. This process relies on the activity of the cytoskeletal filament, microtubules, and their associated motor proteins. These motors are able to walk along microtubule tracks while carrying cellular cargos to enable the fast, regulated transport of these cargos. In cells, these microtubule filaments act as a binding platform for numerous different motor species as well as microtubule-associated proteins (MAPs). In addition, these filaments often form higher order structures, such as microtubule bundles. How motors navigate such complex, crowded ...