Our ultimate goal is to understand how intracellular transport occurs and how defects in transport may lead to the onset and progression of neurodegenerative disease. One cytoskeletal motor that plays an important role in intracellular transport is cytoplasmic dynein, which generates force as it moves toward the minus ends of microtubules. We have previously shown that the ability of cytoplasmic dynein to take multiple steps without dissociating from the microtubule, called processivity, is enhanced by the dynein activator, dynactin. In the previous funding period, we discovered that dynactin actually contains two different microtubule-binding domains and that one of these, the basic domain, is required for dynactin to enhance dynein processivity. Processive long-range movements are especially important in the axonal processes of neurons where cytoplasmic dynein moves retrograde cargo over distances ranging from microns to meters. Genetic lesions in components of the cytoplasmic dynein and dynactin motor machinery have been shown to alter axonal transport and in some cases to result in severe neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), and distal spinal and bulbar muscular atrophy (dSBMA), and Perry syndrome. Our hypothesis is that the basic domain of dynactin p150 acts as a molecular tether to maintain contact between dynein, dynactin, cargo and the microtubule during motility events. During the previous funding period, we expanded our interests beyond dynactin-microtubule interactions to also include regulation of dynein-based transport by additional mechanisms in an attempt to better understand the complexity of cellular dynein-based transport. The goals of this proposal are to test our model of how dynactin functions in dynein-based cargo transport and to determine the roles that additional cellular factors have in dynein-based cargo transport. We will utilize both in vitro and in vivo assays of dynein and dynactin function to test our models for how dynein-based cargo transport normally occurs and how it may be altered during neurodegenerative disease.

Public Health Relevance

A wide range of human health problems from neurodegeneration to cancer may be caused or compounded by the aberrant function of the cytoplasmic dynein and dynactin motor complex. Our studies aim to elucidate how the specific molecular changes resulting from genetic defects alter dynein and dynactin function to cause diseases such as amyotrophic lateral sclerosis (ALS), distal spinal and bulbar muscular atrophy (dSBMA), and Perry Syndrome. A greater understanding of the molecular mechanisms of dynein and dynactin dysfunction underlying these diseases may lead to therapeutic intervention for these neurodegenerative diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS048501-09
Application #
8298482
Study Section
Synapses, Cytoskeleton and Trafficking Study Section (SYN)
Program Officer
Gubitz, Amelie
Project Start
2004-04-01
Project End
2015-08-31
Budget Start
2012-09-01
Budget End
2013-08-31
Support Year
9
Fiscal Year
2012
Total Cost
$318,710
Indirect Cost
$98,910
Name
University of Central Florida
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
150805653
City
Orlando
State
FL
Country
United States
Zip Code
32826
Xu, Jing; Reddy, Babu J N; Anand, Preetha et al. (2012) Casein kinase 2 reverses tail-independent inactivation of kinesin-1. Nat Commun 3:754
Vershinin, Michael; Xu, Jing; Razafsky, David S et al. (2008) Tuning microtubule-based transport through filamentous MAPs: the problem of dynein. Traffic 9:882-92
Dompierre, Jim P; Godin, Juliette D; Charrin, Benedicte C et al. (2007) Histone deacetylase 6 inhibition compensates for the transport deficit in Huntington's disease by increasing tubulin acetylation. J Neurosci 27:3571-83
Bekker, Janine M; Colantonio, Jessica R; Stephens, Andrew D et al. (2007) Direct interaction of Gas11 with microtubules: implications for the dynein regulatory complex. Cell Motil Cytoskeleton 64:461-73
Kincaid, Margaret M; King, Stephen J (2006) Motors and their tethers: the role of secondary binding sites in processive motility. Cell Cycle 5:2733-7
Culver-Hanlon, Tara L; Lex, Stephanie A; Stephens, Andrew D et al. (2006) A microtubule-binding domain in dynactin increases dynein processivity by skating along microtubules. Nat Cell Biol 8:264-70
Mallik, Roop; Petrov, Dmitri; Lex, S A et al. (2005) Building complexity: an in vitro study of cytoplasmic dynein with in vivo implications. Curr Biol 15:2075-85