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Thesis (Ph.D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Pharmacology and Toxicology. Title from title-page of electronic thesis. Bibliography: leaves 130-143.

Thesis (Ph. D.)--University of Virginia, 2001. / Includes bibliographical references (leaves 123-140). Also available online through Digital Dissertations.

Septins are a family of guanine nucleotide-binding proteins that function in eukaryotic cell division, where they form a high-order cortical structure at the site of division, which is essential in most eukaryotes. Expanded roles have evolved for septins in metazoans, where they also have essential functions in terminally-differentiated cell types, such as neurons and spermatozoa. Specific details of septin function are lacking in most roles described, due at least in part to the limited number of characterized binding partners. In this work, yeast two-hybrid screens and pull-downs from tissue homogenate were used to identify novel septin binding partners for subsequent characterization. The neuron-enriched septin, SEPT5, interacted directly with SUMO E3 ligases of the PIAS family. However, I was not able to demonstrate endogenous sumoylation of SEPT5 and SUMO isoforms did not concentrate with the septins during cytokinesis. SEPT5 also interacted with a novel septin, SEPT12, which I further characterized to be testis-specific and localized to the annulus in mature spermatozoa. Further, using SEPT12-specific reagents, I determined that the annulus forms via sequestration and subsequent segregation from the Golgi during spermiogenesis. SEPT9 pull-downs identified another novel testis-specific septin, SEPT14. Reagents specific to SEPT2 and SEPT9 also revealed a septin-rich structure in the seminiferous epithelium in close association with the ectoplasmic specialization. The specific role of septins in this structure awaits further characterization. Several other intriguing candidate septin-interaction partners were identified and the further study of their possible in vivo interaction with septins may provide substantial insight into the mechanisms of septin function in eukaryotes.

Septins are a family of guanine nucleotide-binding proteins that function in eukaryotic cell division, where they form a high-order cortical structure at the site of division, which is essential in most eukaryotes. Expanded roles have evolved for septins in metazoans, where they also have essential functions in terminally-differentiated cell types, such as neurons and spermatozoa. Specific details of septin function are lacking in most roles described, due at least in part to the limited number of characterized binding partners. In this work, yeast two-hybrid screens and pull-downs from tissue homogenate were used to identify novel septin binding partners for subsequent characterization. The neuron-enriched septin, SEPT5, interacted directly with SUMO E3 ligases of the PIAS family. However, I was not able to demonstrate endogenous sumoylation of SEPT5 and SUMO isoforms did not concentrate with the septins during cytokinesis. SEPT5 also interacted with a novel septin, SEPT12, which I further characterized to be testis-specific and localized to the annulus in mature spermatozoa. Further, using SEPT12-specific reagents, I determined that the annulus forms via sequestration and subsequent segregation from the Golgi during spermiogenesis. SEPT9 pull-downs identified another novel testis-specific septin, SEPT14. Reagents specific to SEPT2 and SEPT9 also revealed a septin-rich structure in the seminiferous epithelium in close association with the ectoplasmic specialization. The specific role of septins in this structure awaits further characterization. Several other intriguing candidate septin-interaction partners were identified and the further study of their possible in vivo interaction with septins may provide substantial insight into the mechanisms of septin function in eukaryotes.

Dissertation (Ph.D.).--University of Texas Graduate School of Biomedical Sciences at San Antonio, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2004. / Vita. Bibliography: References located at the end of each chapter.

Thesis (Ph. D.)--University of Virginia, 1997. / Spine title: Human A2A adenosine receptors. Includes bibliographical references (115-135). Also available online through Digital Dissertations.

Bochum, Univ., Diss., 2005.

Thesis (Ph. D.)--Case Western Reserve University, 2007. / [School of Medicine] Department of Neurosciences. Includes bibliographical references. Available online via OhioLINK's ETD Center.