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Identification of an amyloid fibril forming segment of human Pmel17 repeat domain (RPT domain)

Nikolaos N Louros1, Vassiliki A Iconomidou1

  • 1Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens, 157 01, Greece.

Biopolymers
|September 24, 2015
PubMed

Insights

Researchers identified a specific peptide segment within the Pmel17 protein that self-assembles into amyloid fibrils. This finding sheds light on the mechanism of pigment deposition and Pmel17 polymerization.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Structural Biology

Background:

  • Pmel17 protein is crucial for pigment deposition, forming amyloid fibrils.
  • Pmel17 polymerization occurs in melanosomes under acidic conditions.
  • The Pmel17 RPT domain is implicated in forming the fibrous matrix.

Purpose of the Study:

  • To investigate the mechanism of Pmel17 polymerization.
  • To identify specific regions within the RPT domain responsible for fibril formation.

Main Methods:

  • Electron microscopy
  • X-ray fiber diffraction
  • Congo red staining
  • ATR FT-IR spectroscopy
  • Analysis of a specific peptide segment ((405) VSIVVLSGT(413))

Main Results:

  • An aggregation-prone peptide segment ((405) VSIVVLSGT(413)) was identified in the Pmel17 RPT domain.
  • This peptide segment self-assembles into fibrils with amyloidogenic properties.
  • Experimental data supports the fibril-forming capability of the identified peptide.

Conclusions:

  • The (405) VSIVVLSGT(413) peptide segment plays a key role in Pmel17 RPT domain fibrillogenesis.
  • This peptide segment is likely essential for the formation of Pmel17 amyloid fibrils.
  • Understanding this mechanism contributes to knowledge of pigment deposition processes.
Keywords:
amyloid fibrilselectron microscopymelaninmelanosomes“aggregation-prone” peptide-analogue

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