The Identification of a New Molecular Tool to Investigate the Role of Actin and Microtubule Cytoskeletons in the Endocytosis Pathway of the Pathogenic Ungus Ustilago Maydis
Clark, Natalie
Date: 30 May 2014
Publisher
University of Exeter
Degree Title
PhD in Biological Sciences
Abstract
Endocytosis is essential for the pathogenic development of Ustilago maydis.
It has been shown that the initiation of pathogenicity relies upon the ability of
the cell to recognize pheromone (a1 or a2) released from its mating partner
and subsequently to form conjugated hyphae. The actin and microtubule
cytoskeleton plays an ...
Endocytosis is essential for the pathogenic development of Ustilago maydis.
It has been shown that the initiation of pathogenicity relies upon the ability of
the cell to recognize pheromone (a1 or a2) released from its mating partner
and subsequently to form conjugated hyphae. The actin and microtubule
cytoskeleton plays an essential role in all aspects of cell growth. A component
of the actin cytoskeleton, the filamentous actin is required for cell-cell fusion,
whereas the molecular motors, kinesin and dynein, move along microtubules
and provide the long distance transport of many proteins and they are
important in cell growth and pathogenicity.
In this thesis, we investigated the role of the cytoskeleton in endocytosis and
a1 pheromone transport, using a fluorescently labelled derivative of the a1
pheromone. We confirmed that uptake of the a1 pheromone is also receptormediated.
In addition, we have shown that pheromone transport towards the
cellular vacuole requires the actin and microtubule cytoskeletons.
Furthermore, we revealed that the microtubule-dependent motors kinesin-1
and kinesin-3 and dynein were shown to be essential in the delivery of the
pheromone to vacuoles. Moreover, a mutation in the early endosomal protein
Yup1 gene causes a stop in delivery of the synthetic pheromone to the
vacuole. This suggests that it travels with early endosomes. Within the actin
cytoskeleton, we analysed the dynamics of actin patches in the presence of
the synthetic pheromone and found that the dynamics of the patches
increased significantly. Additionally, in the presence of an over-expression of
the tail domain of the molecular motor myosin-5, the dynamics of the patches
were significantly reduced and their intensity diminished.
Doctoral Theses
Doctoral College
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