Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 196-235).

Synapse development is a stepwise process that requires the recruitment of key synaptic components to active zones, followed by continual maintenance of these structures to maintain connectivity and stability throughout the life of the organisms. Early synapse development requires the recruitment of early scaffolding proteins to establish stable connectivity as well as provide sites of recruitment of other vital synaptic proteins. One of the earliest proteins to be localized to the synapse is the conserved protein Syd-1. Syd-1 proteins contain a Rho GTPase activating protein (GAP)-like domain of unclear significance. Here I show that Drosophila Syd-1 interacts with all six fly Rhos and has GAP activity towards RAC1. I then show that lacks GAP activity localizes normally to presynaptic sites and is sufficient to recruit Nrx-1 but fails to cluster Brp normally and genetically interacts with RAC1 in vivo. I conclude that contrary to previous models, the GAP domain of fly Syd-1 is active and required for presynaptic development. Additionally, I’ve identified a previously uncharacterized protein, Vezl, as being critical for retrograde axonal transport and synaptic maintenance. I found that Vezl required for normal neuronal growth and that vezl loss resulted in decreased neuron size and the formation of swollen neuronal terminals that accumulated membrane markers and axonal transport cargo. I found that vezl mutants specifically retrograde transport of cargo and particularly affected signaling endosomes. The signaling endosomes were unable to initiate retrograde transport in vezl mutants and remained stuck within the distal boutons unable to relay their signaling peptides back to the nucleus. I conclude that Vezl is serving a role in attaching retrograde cargo to dynein and the microtubules specifically at neuron tips so that they can undergo retrograde axonal transport. This dissertation includes previously published and unpublished co-authored material. / 2020-09-06

No description available.

No description available.

No description available.

微小管結合タンパク質の1つであるタウは、神経細胞の軸索に特異的に局在している。タウの軸索局在化分子機序を解明するために、外因性タウを神経細胞の発達初期に一時的に発現させ、軸索特異的に局在させる方法を構築した。この方法を用い、proline rich region 2 (PRR2)がタウの軸索局在化に重要であること、PRR2のリン酸化が軸索への移動に関与することを示唆した。またこの系の確立は局在や細胞内動態などの検討を行うことを可能にした。 / Microtubule-associated protein tau localizes specifically to neuronal axons. In order to elucidate the molecular mechanism of the axon localization of tau, we constructed an expression system for axon specific localization of exogenous tau in immature neurons in culture. Using this system, it suggested that the proline rich region 2 (PRR2) and phosphorylation of PRR2, which contains important phosphorylation sites, is critical for the localization. In the future, this experimental system will contribute greatly to the study of tau in normal and in the pathology of Alzheimer's disease. / 博士(理学) / Doctor of Philosophy in Science / 同志社大学 / Doshisha University

Aging and Alzheimer’s disease (AD) are associated with decreased cognitive function and neural degeneration. The basal forebrain is one of the first areas of the brain to degenerate in AD and depends on the neurotrophin brain-derived neurotrophic factor (BDNF) for survival. Loss of BDNF transport from target neurons may contribute to basal forebrain cholinergic neuron (BFCN) vulnerability in AD and aging. Oxidative stress is associated with cholinergic dysfunction and cognitive decline in aging and AD, and it is possible that oxidative stress may contribute to BDNF transport deficits in BFCNs. BFCNs are grown in microfluidic chambers that allow isolation of BFCN soma and axon terminals so transport of biotinylated and fluorescently labelled BDNF can be quantified. The objective of my research was to determine if oxidative stress induces BDNF retrograde transport deficits in BFCNs, and the mechanism behind this effect. I found that oxidative stress does reduce BDNF retrograde transport in BFCNs. Because it has previously been shown that aged BFCNs have decreased BDNF transport and downregulate the BDNF receptor TrkB, expression of both TrkB and p75NTR receptors was tested following oxidative stress using immunocytochemistry (ICC) and western blotting. This experiment showed that oxidative stress does not affect p75NTR or TrkB receptor levels. A likely alternative is that oxidative stress may lead to alterations in the transport machinery responsible for retrograde BDNF transport. I hypothesized that oxidative stress decreases retrograde axonal transport of BDNF via increased insulin-like growth factor 1 receptor (IGF1R) activity, which decreases the protein expression of the adaptor proteins BICD1 and Hook1 by inhibiting GSK3β activity via the PI3K-Akt pathway. ICC and western blotting showed that oxidative stress has no effect on either BICD1 or Hook1 levels. Future directions of this work involve further studying the involvement of the IGF1R pathway in oxidative stress, and the effect on other proteins involved in BDNF transport, including htt and DISC1. / Thesis / Master of Science (MSc)

No description available.

No description available.

No description available.