Amyloids are insoluble fibrous protein aggregates, and their accumulation is associated with amyloidosis and many neurodegenerative diseases, including Alzheimer's disease. Here, we report that smooth muscle titin (SMT, 500 kDa) from chicken gizzard forms amyloid aggregates <em>in vitro</em>. This conclusion is supported by electron microscopy data, fluorescence analysis using thioflavin T, Congo red spectroscopy, and X-ray diffraction. Our dynamic light scattering (DLS) data show that titin forms <em>in vitro </em>amyloid aggregates with a hydrodynamic radius (Rh) of about 700-4500 nm. The initial titin aggregates with Rh ~ 700 nm were observed beyond first 20 min its aggregation that shows a high rate of amyloid formation by this protein. We also showed using confocal microscopy the cytotoxic effect of SMT amyloid aggregates on smooth muscle cells from bovine aorta. This effect involves the disorganization of the actin cytoskeleton and result is cell damage. Cumulatively our results indicate that titin may be involved in generation of amyloidosis in smooth muscles.
- amyloid aggregates
- smooth muscle titin
- ©2016 The Author(s)
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