Thesis (M.Med.Sc.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 82-86). Also available in print.

Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Zhu, Cheng; Committee Member: Barry, Bridgette; Committee Member: Boyan, Barbara; Committee Member: McEver, Rodger; Committee Member: McIntire, Larry. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M.Sc.) - University of Queensland, 2003. / Includes bibliography.

Thesis (M.S.)--Brigham Young University. Dept. of Mathematics, 2005. / Includes bibliographical references (p. 56).

In the mammalian seminiferous epithelium, the cytoplasm of Sertoli cells adjacent to sites of intercellular attachment exhibits unique structural attributes. In each of these regions, a layer of hexagonally packed actin filaments lies situated between a cistern of endoplasmic reticulum and the plasma membrane. The filament layer together with the reticulum and adjacent plasma membrane are collectively termed an "ectoplasmic specialization". Ectoplasmic specializations occur in apical Sertoli cell regions at sites of attachment to spermatids and basally at sites of attachment to adjacent Sertoli cells. Ectoplasmic specializations have been hypothesized to be actin associated intercellular adhesion junctions. If this is true, molecular components that characterize actin associated adhesion junctions in general should be present in ectoplasmic specializations. In this study, I tested this prediction in two ways. First, I investigated whether or not the protein vinculin is co-distributed with actin filament bundles in ectoplasmic specializations of the ground squirrel. Second, I immunologically probed ectoplasmic specializations for three cell adhesion molecules (CAMs) that are commonly found in regions of intercellular adhesion in other tissues. My results indicate that vinculin is co-distributed with actin in Sertoli cell regions attached to spermatids. These data are consistent with the conclusion that vinculin is a component of ectoplasmic specializations and, therefore, with the hypothesis that the latter structures are a form of actin associated adhesion junction. Experiments using probes for the CAMs indicate that E-cadherin, A-CAM and N-CAM are probably not present in ectoplasmic specializations. The adhesion molecule at these sites may be a different member of the known CAMs or an as yet unidentified CAM. Based on data presented here and elsewhere indicating that ectoplasmic specializations are a form of actin associated adhesion junction, I describe the elaborate changes that occur in constituent filament bundles at sites of attachment to spermatids of the ground squirrel and interprete them in the context of the adhesion hypothesis. During the course of the co-localization studies described above, I observed that vinculin and actin are co-distributed at certain sites of intercellular attachment between interstitial cells of Leydig in the ground squirrel testis. Moreover, at the ultrastructural level I found these sites correspond to microfilament rich junction regions. These observations are consistent with the conclusion that actin associated intercellular adhesion junctions exist between interstitial cells of Leydig in the ground squirrel testis. / Medicine, Faculty of / Graduate

No description available.

N cadherin is one member of the cadherin superfamily. It like other classes of cell adhesion molecules (CAMs and FAKs) is responsible for cell-cell adhesion ... specifically during early morphogenesis. · N cadherin is the designated cell adhesion molecule for neural tissue. It, in concert with several signal transduction pathways, allows an early neurite to follow chemical and adhesive gradients from its origin to its destination. N cadherin can only operate as an affector of neurite or growth cone guidance when in complex. As a mediator of information from the outside environment to the inside cytoskeleton, N cadherin must rely on cooperation with PTPµ ( a protein tyrosine phosphatase), ~ and a catenin to make firm connection with actin. With that connection established, an early growth cone can make decisions based on chemical and adhesive cues. Movement of the growth cone, as a function of adhesion or "homophilic binding," is termed "haptotaxis." Intracellular concentrations of catenin pools and the activity of two pathways (Src and Wnt) regulate the entire system. Based on studies and experimental data, a model, with respect to complex orientation and behavior is proposed.

published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Molecular Biology / Master / Master of Philosophy

No description available.