No description available.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 172-199). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 172-199). Also available on the Internet.

The transport of material across the plasma membrane and between subcellular compartments is a major trafficking event by which cells communicate, regulate developmental processes and maintain homeostasis. Clathrin-coated vesicles select and traffic proteins to specific compartments in eukaryotic cells. Recently a large number of proteins have been identified that serve as clathrin adaptors and accessory proteins. Information regarding the interaction between individual clathrin adaptors and accessory proteins during coated pit formation is currently lacking. Here we investigated the intracellular role of one clathrin adaptor, Dictyostelium discoideum Hip1r, and identified a functional relationship between Hip1r and a second clathrin adaptor, epsin. Hip1r is phosphorylated and localizes to punctae on the plasma membrane that also contain epsin. Moreover, expression of the NH₂-terminal ENTH domain of epsin alone was sufficient to restore both the phosphorylation and the restricted localization of Hip1r to the plasma membrane. Analysis of the individual Hip1r domains demonstrated the phosphorylation event is also dependent upon the expression of the central coiled-coil region of the Hip1r. During development, Hip1r null cells form mature fruiting bodies that yield defective spores. While the mutant spores contain both cellulose and at least one protein secreted from prespore vesicles, spore coats lack the organized fibrils typical of wild type spores. Moreover, Hip1r spores are round, rather than ovoid, and exhibit decreased viability. Domain analysis of Hip1r in conjunction with investigation of phenotypes associated with a Hip1r/epsin double mutant reveal a requirement for full length Hip1r in the production of robust spores. Results from this study suggest that the Hip1r protein functions with epsin during cellular events in both growing and developing Dictyostelium cells and reveals a previously unidentified interaction between two clathrin adaptors. / text

No description available.

No description available.

The cAMP binding protein CABP1 isolated from Dictyostelium discoideum consists of two subunits, CABP1A and CABP1B, which are produced from a single gene by an unusual splicing mechanism. To characterize this mechanism, an actin-CABP1 fusion gene was constructed and introduced into D. discoideum cells by DNA-mediated transformation. Analysis of these cells demonstrated that the transcripts derived from the fusion gene were properly processed to generate both CABP1A and CABP1B. However, when the 5$ sp prime$ splice site in the gene was mutated to conform to the D. discoideum consensus, only CABP1B was produced. These results suggest that the splicing event is regulated by the 5$ sp prime$ splice site. By screening a cDNA library under conditions of reduced stringency with a sequence encoding CABP1, clones which code for two closely related molecules were isolated. Hybrid selection experiments indicated that these cDNAs encode polypeptides with molecular weights of 34,000 (p34) and 31,000 (p31), both of which are recognized by anti-CABP1 antibodies. Similar to the two subunits of CABP1, these two molecules appear to be encoded by a single gene and are probably generated by the same splicing mechanism described above. The CABP1 and p34/31 genes probably arose by duplication. Disruption of the gene which encodes p34 and p31 demonstrated that these two polypeptides appear to play a role in both growth and development of D. discoideum.

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1968. / Bibliography: leaves 190-195. / xiii, 195 l illus

Dissertation (Ph.D.)--University of Toledo, 2007. / "In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biomedical Sciences." Title from title page of PDF document. Bibliography: p. 117-147.

Thesis (M.S.) in Biochemistry--University of Maine, 2007. / Includes vita. Includes bibliographical references (leaves 96-97).