Kinesin-1 is a microtubule-based motor essential for cellular organization and function. Which of three possible heavy chain (KHC) and four possible light chain (KLC) homodimer subunits assemble to form heterotetramers and the unique roles particular Kinesin-1 holoenzymes perform in neural tissues is largely unknown. I characterized functions of neuronally-enriched subunits KLC1 and Kinesin-1C in cultured murine KLC1-/- and Kinesin-1C-/- hippocampal neurons and human embryonic stem cell (hESC)-derived neural cultures. In both mouse and human cultures reduction in KLC1 correlated with reduction in Kinesin-1C; in Kinesin-1C-/- mouse cultures KLC1 levels were reduced, suggesting these subunits may function together. Extending on previous analyses of mice lacking these full length proteins, I examined the effect of reduction in full KLC1 and Kinesin-1C on mouse neuron development and production of human neural progenitors and neural cultures. I found that while Kinesin-1C and KLC1 may play minor roles in the neuronal development of murine neurons, reduction of KLC1 in hESC impairs proliferative capacity of neural precursor (NP) progeny suggesting that KLC1 may be essential for NP maintenance. Neuron-like cells in neural cultures derived from KLC1-reduced hESC have less microtubule associated proteins (MAPs) and shorter projections, suggesting KLC1 and Kinesin-1C may be required for proper development of human neurons. Analyses of adult mice with reduced full length KLC1 suggest this subunit may also influence levels of Amyloid-β (Aβ) and phosphorylated Tau (pTau), the two principle components of Alzheimer's Disease (AD) hallmark lesions. Therefore I used mouse neurons and KLC1-reduced human neural cultures to evaluate levels of these proteins and the Aβ parent molecule amyloid precursor protein (APP). While I found no difference in Tau levels in murine neurons, in human neural cultures Tau was reduced along with other MAPs, suggesting KLC1 may impact Tau levels via more general effects on microtubules. While no change in APP levels was observed in mouse KLC1-/- neurons, mouse Kinesin-1C-/- neurons and human KLC1-reduced neural cultures exhibited lower extracellular Aβ/p3 which may be due to lower APP levels. Altogether my data suggest that Kinesin-1C and KLC1 may form functional Kinesin-1 holoenzymes that affect proliferation of NPs, neuronal development and APP levels.
|Advisor:||Goldstein, Lawrence S.|
|Commitee:||Cleveland, Don W., Farquhar, Marilyn G., Koo, Edward H., Wang, Jean Y.|
|School:||University of California, San Diego|
|School Location:||United States -- California|
|Source:||DAI-B 72/09, Dissertation Abstracts International|
|Subjects:||Neurosciences, Cellular biology, Developmental biology|
|Keywords:||Fluorescence-activated cell sorting, Lentiviral vectors, Neural stem cells, Neuronal development, Pluripotent stem cells, Progenitor cells|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be