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Dynactin is a processivity factor for dynein in vivo
Title
Dynactin is a processivity factor for dynein in vivo.
Creator
Fulton, Edward., Harriet L. Wilkes Honors College
Abstract/Description
Dynein is a motor protein responsible for microtubule-based minus-end directed trafficking in eukaryotic cells. Dynactin is a protein complex involved in mitosis, embryonic development, intracellular trafficking and anchoring microtubules at the centrosome. While dynactin is widely recognized to improve the array of cargo with which dynein can associate, there has been some dispute over whether dynactin, which binds both dynein and microtubules, improves the distance that dynein can travel...
Show moreDynein is a motor protein responsible for microtubule-based minus-end directed trafficking in eukaryotic cells. Dynactin is a protein complex involved in mitosis, embryonic development, intracellular trafficking and anchoring microtubules at the centrosome. While dynactin is widely recognized to improve the array of cargo with which dynein can associate, there has been some dispute over whether dynactin, which binds both dynein and microtubules, improves the distance that dynein can travel processively in the act of cargo trafficking before it dissociates from its microtubule. In this study, we compare movement parameters of wild type dynein-based vesicle movements with movements in cells where expression of dynactin's microtubule binding subunit, p150glued, has been knocked down. We find that dynactin does act as a processivity factor for dynein by increasing the distance that dynein can travel smoothly in a single movement event, but does not increase dynein's velocity.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/209990
Subject Headings
Cell organelles, Formation, Microtubules, Cytoskeletal proteins, Molecular biology
Format
Document (PDF)
Knockdown of dynactin's p150[Glued] subunit abrogates microtubule organization
Title
Knockdown of dynactin's p150[Glued] subunit abrogates microtubule organization.
Creator
Roeckner, Jared Todd., Harriet L. Wilkes Honors College
Abstract/Description
Dynactin is a multifunctional protein complex composed of at least 11 different subunits. Dynactin functions as a cofactor for cytoplasmic dynein facilitating long-range vesicle movements, microtubule anchoring, endomembrane localization, and mitotic progression. Previous studies have shown that dynactin binds to microtubules at the centrosome maintaining a radial array in interphase. The p150Glued subunit contains two distinct microtubule-binding sequences named CAP-Gly and Basic. While both...
Show moreDynactin is a multifunctional protein complex composed of at least 11 different subunits. Dynactin functions as a cofactor for cytoplasmic dynein facilitating long-range vesicle movements, microtubule anchoring, endomembrane localization, and mitotic progression. Previous studies have shown that dynactin binds to microtubules at the centrosome maintaining a radial array in interphase. The p150Glued subunit contains two distinct microtubule-binding sequences named CAP-Gly and Basic. While both domains can interact with microtubule, CAP-Gly has a much greater affinity for binding to microtubules, suggesting that the two domains may be active for different dynactin-based functions within the cell. Using siRNA, we found that knockdown of p150Glued was sufficient to alter the maintenance of radial microtubule arrays, cause an increase in centrosome number and mitotic index. In the future we will replace the endogenous protein with versions lacking the CAP-Gly or Basic domains to investigate the contribution of each to microtubule anchoring and cytoskeletal architecture.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/209998
Subject Headings
Cytoskeletal proteins, Cell organelles, Formation, Microtubules, Molecular biology
Format
Document (PDF)
You keep me hangin' on
Title
You keep me hangin' on: dynactin's p24 is essential for microtube anchoring.
Creator
Le, Ariel., Harriet L. Wilkes Honors College
Abstract/Description
Dynactin is a multisubunit protein complex that functions as a processivity cofactor to cytoplasmic dynein, assisting in vesicle transport and cell division. Independent of dynein,dynactin also serves to anchor microtubules to the centrosome. The functions of the majority of dynactin's subunits have been described to a certain degree ; however, the p24 subunit remains largely uncharacterized. Among the few things that are known about p24 are that it has a predicted molecular weight of about...
Show moreDynactin is a multisubunit protein complex that functions as a processivity cofactor to cytoplasmic dynein, assisting in vesicle transport and cell division. Independent of dynein,dynactin also serves to anchor microtubules to the centrosome. The functions of the majority of dynactin's subunits have been described to a certain degree ; however, the p24 subunit remains largely uncharacterized. Among the few things that are known about p24 are that it has a predicted molecular weight of about 20,822 Da, forms an a-helix, and binds directly to the p150[Glued] subunit. In order to explore its function further, we have performed shRNA-mediated knockdown, and fluorescent microscopy. We observe that microtubule disorganization is amplified due to the loss of p24. Our findings support the model that p24 serves as reinforcement to stabilize p150[Glued] at the centrosome.
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Date Issued
2012
PURL
http://purl.flvc.org/FAU/3355592
Subject Headings
Cytoskeletal proteins, Cell organellles, Formation, Microtubules, Molecular biology
Format
Document (PDF)