Associated with:

• Ulcerative Colitis

• Colon Autoimmunity

• Inflammatory Bowel Disease

Tropomyosin is a cytoskeletal microfilamental protein that regulates actin mechanics. Tropomyosin plays an important role in muscle contraction. Tropomyosin, along with the troponin complex, works with actin in muscle fibers and manages muscle contraction by regulating the binding of myosin. Tropomyosin isoforms are involved in the stabilization of actin filaments, intracellular organelle movement, cell-shape maintenance and cytokinesis.

Clinical Significance:

The autoantibodies of Tropomyosin present in the sera of patients with Ulcerative Colitis have been shown to destroy Cr-labeled colonic adenocarcinoma cells (LS180) by antibody and complement mediated lysis. Due to the high familial incidence of Ulcerative Colitis, first degree relatives of patients diagnosed with Ulcerative Colitis, should be assessed for Tropomyosin antibodies.

References:

1. Das, Dasgupta, Mandal, et al. Autoimmunity to cytoskeletal protein tropomyosin. A clue to the pathogenetic mechanism for ulcerative colitis. J Immunol, 1993; 150:2487-2493.

2. Ebert, et al. Autoantibodies against human tropomyosin isoform 5 in ulcerative colitis destroys colonic epithelial cells through antibody and complement-mediated lysis. Cellular Immunol, 2006; 244:43-49.

3. Fenderson, et al. Tropomyosin shares immunologic epitopes with group A streptococcal M proteins. J Immunol, 1989; 142(7):2475-2481.

4. Fujta, et al. Enzyme-linked immunosorbent assay for anti-tropomyosin antibodies and its clinical application to various heart diseases. Clinica Chimica Acta, 2000; 299(1-2):179-192.

5. Mirza, Sastri, Lin, et al. Autoimmunity against human tropomyosin isoforms in ulcerative colitis. Inflamm Bowel Dis, 2006; 12(11):1036-1043.

6. Peattie, et al. Ultrastructural localization of giardins to the edges of disk microribbons of Giarida lamblia and the nucleotide and deduced protein sequence of alpha giardin. J Cell Biol, 1989; 109(5):2323-2335.

7. Liu, et al. Tropomyosin from tilapia (Oreochromis mossambicus) as an allergen. Clin Exp Allergy, 2013; 43:365-377.

8. Kovvali and Das. Molecular mimicry may contribute to pathogenesis of ulcerative colitis. FEBS Letters, 2005; 579:2261-2266.