The mutant mouse dystonia musculorum (dt) suffers from a severe hereditary sensory neuropathy. The mice display progressive loss of limb coordination starting in the second week of life. Dorsal root ganglia of dt mice are considerably smaller in size than those of wild type mice with organelles and empty vacuoles accumulating within sensory axons. Focal axonal swellings filled with neurofilaments, mitochondria and membrane bound dense bodies are hallmarks of the pathology of these mice. The disorganization of the cytoskeleton precedes neurodegeneration in the mutant mice. The gene that is mutated in dt mice is called dystonin, and is also known as bullous pemphigoid antigen 1 (BPAG1). BPAG1 is a member of the plakin family of cytoskeletal linker proteins. Plakin family members have a characteristic plakin domain that can interact with a variety of cell adhesion molecules, as well as members of the armadillo-repeat domain containing protein family (catenin family). In addition, various plakins have domains that can bind to actin microfilaments, microtubules and intermediate filaments. In epithelial cells, BPAG1-e is involved in anchoring keratin intermediate filaments to the hemidesmosomes. Why does the deletion of a hemidesmosomal protein cause neuronal degeneration? To investigate this question, we have analyzed the BPAG1 locus in detail. We found that by tissue specific splicing, it encodes a variety of isoforms with different combinations of the various interacting domains. There are two isoforms expressed in the nervous system: the major isoform, BPAG1-a and BPAG1-n, which is expressed at lower levels than BPAG1-a. BPAG1-b is the largest isoform and is highly expressed in muscles. Alternatively spliced 5' and 3' ends that affect the ABD and MTBD respectively can lead to additional isoforms of BPAG1-a, BPAG1-b and BPAG1-n. In this proposal, we will study the function of the neuronal isoforms in more detail to understand why mutations of this protein result in neuronal degeneration. This proposal focuses on the cause for the mouse mutant dystonia musculorum (dt) and is therefore in the realm of the Program Announcement initiative PA- 02-156: """"""""Studies into the causes and mechanisms of dystonia."""""""" In particular, the proposal meets the criteria of the second research area targeted by the PA: """"""""Identification of proteins that interact with dystonia-related cellular factors (genes, proteins) and determination of their coordinated function.""""""""

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS047711-02
Application #
6936442
Study Section
Special Emphasis Panel (ZRG1-MDCN-B (02))
Program Officer
Tagle, Danilo A
Project Start
2004-08-15
Project End
2008-06-30
Budget Start
2005-07-01
Budget End
2006-06-30
Support Year
2
Fiscal Year
2005
Total Cost
$330,171
Indirect Cost
Name
Columbia University (N.Y.)
Department
Pathology
Type
Schools of Medicine
DUNS #
621889815
City
New York
State
NY
Country
United States
Zip Code
10032
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Steiner-Champliaud, Marie-France; Schneider, Yann; Favre, Bertrand et al. (2010) BPAG1 isoform-b: complex distribution pattern in striated and heart muscle and association with plectin and alpha-actinin. Exp Cell Res 316:297-313
Goryunov, Dmitry; He, Cui-Zhen; Lin, Chyuan-Sheng et al. (2010) Nervous-tissue-specific elimination of microtubule-actin crosslinking factor 1a results in multiple developmental defects in the mouse brain. Mol Cell Neurosci 44:1-14
Jefferson, Julius J; Ciatto, Carlo; Shapiro, Lawrence et al. (2007) Structural analysis of the plakin domain of bullous pemphigoid antigen1 (BPAG1) suggests that plakins are members of the spectrin superfamily. J Mol Biol 366:244-57
Jefferson, Julius J; Leung, Conrad L; Liem, Ronald K H (2006) Dissecting the sequence specific functions of alternative N-terminal isoforms of mouse bullous pemphigoid antigen 1. Exp Cell Res 312:2712-25