Pemphigus is a class of devastating epidermal blistering diseases in which autoantibodies are generated against cell-cell adhesion molecules present in the skin and mucous membranes. Pemphigus IgG target desmosomes, a structure that couples the keratin intermediate filament network to regions of strong cell-cell adhesion. In pemphigus vulgaris (PV), the primary target of the autoantibodies is desmoglein-3 (Dsg3), a member of the desmosomal cadherin subfamily of adhesion molecules. The work outlined in this proposal investigates the fundamental mechanisms of desmosome assembly and disassembly in human keratinocytes and how these processes are disrupted by PV patient IgG. A major focus of the proposal is how desmosomal proteins are targeted to lipid raft membrane microdomains, and how the association of desmosomal proteins with lipid rafts regulates desmosome formation and disassembly in response to pemphigus IgG. We hypothesize that desmosomal protein targeting to lipid rafts is essential for desmosomal protein clustering during desmosome assembly, and for endocytosis of desmosomal cadherins during disassembly in response to PV IgG. We will utilize PV patient samples, including skin biopsies and purified PV IgG, to determine how PV IgG affect desmosomes in human skin and to determine how PV IgG impact Dsg3 adhesive function using cell biological and single molecular biophysical approaches. Additionally, we will define the amino-acid determinants in Dsg3 that target the protein to lipid rafts and, using mutants deficient in raft targeting, determine how association with lipid rafts impacts desmoglein function. Similar studies will be performed with desmosomal plaque proteins such as the plakophilins and desmoplakin to determine the hierarchy of desmosome protein association with lipid raft membrane domains. These experimental approaches will be integrated to advance our understanding of basic cellular mechanisms of keratinocyte adhesion and to reveal how these mechanism are compromised in a serious epidermal blistering disorder.

Public Health Relevance

These studies are designed to generate new insights into the basic cellular mechanisms that regulate cell-cell interactions, and to expose new therapeutic targets for the treatment of pemphigus and other skin diseases characterized by skin fragility.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
2R01AR048266-11A1
Application #
8693177
Study Section
Arthritis, Connective Tissue and Skin Study Section (ACTS)
Program Officer
Cibotti, Ricardo
Project Start
2002-08-01
Project End
2019-03-31
Budget Start
2014-04-01
Budget End
2015-03-31
Support Year
11
Fiscal Year
2014
Total Cost
$459,075
Indirect Cost
$162,104
Name
Emory University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Cadwell, Chantel M; Jenkins, Paul M; Bennett, Vann et al. (2016) Ankyrin-G Inhibits Endocytosis of Cadherin Dimers. J Biol Chem 291:691-704
Roberts, Brett J; Svoboda, Robert A; Overmiller, Andrew M et al. (2016) Palmitoylation of Desmoglein 2 Is a Regulator of Assembly Dynamics and Protein Turnover. J Biol Chem 291:24857-24865
Stahley, Sara N; Bartle, Emily I; Atkinson, Claire E et al. (2016) Molecular organization of the desmosome as revealed by direct stochastic optical reconstruction microscopy. J Cell Sci 129:2897-904
Stahley, Sara N; Warren, Maxine F; Feldman, Ron J et al. (2016) Super-Resolution Microscopy Reveals Altered Desmosomal Protein Organization in Tissue from Patients with Pemphigus Vulgaris. J Invest Dermatol 136:59-66
Stahley, Sara N; Warren, Maxine F; Feldman, Ron J et al. (2015) Super-Resolution Microscopy Reveals Altered Desmosomal Protein Organization in Pemphigus Vulgaris Patient Tissue. J Invest Dermatol :
Stahley, Sara N; Kowalczyk, Andrew P (2015) Desmosomes in acquired disease. Cell Tissue Res 360:439-56
Stahley, Sara N; Saito, Masataka; Faundez, Victor et al. (2014) Desmosome assembly and disassembly are membrane raft-dependent. PLoS One 9:e87809
Tucker, Dana K; Stahley, Sara N; Kowalczyk, Andrew P (2014) Plakophilin-1 protects keratinocytes from pemphigus vulgaris IgG by forming calcium-independent desmosomes. J Invest Dermatol 134:1033-43
Kowalczyk, Andrew P; Green, Kathleen J (2013) Structure, function, and regulation of desmosomes. Prog Mol Biol Transl Sci 116:95-118
Kowalczyk, Andrew P; Nanes, Benjamin A (2012) Adherens junction turnover: regulating adhesion through cadherin endocytosis, degradation, and recycling. Subcell Biochem 60:197-222

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