Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL
| Autor: | Xinran Liu, Ralf M. Leonhardt, Morven Graham, Susan M. Mitchell |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Protein Folding
Amyloid Protein subunit Proteolysis Science Endoplasmic Reticulum Article Protein Domains medicine Humans Amino Acid Sequence Amino Acids Melanosome chemistry.chemical_classification Multidisciplinary Multivesicular bodies Melanosomes medicine.diagnostic_test Endoplasmic reticulum Mutagenesis Amino acid PMEL Cell biology Protein Transport chemistry Mutation Medicine Protein aggregation Lysosomes Subcellular Fractions gp100 Melanoma Antigen |
| Zdroj: | Scientific Reports Scientific Reports, Vol 11, Iss 1, Pp 1-13 (2021) |
| ISSN: | 2045-2322 |
| Popis: | The pigment cell-specific protein PMEL forms a functional amyloid matrix in melanosomes onto which the pigment melanin is deposited. The amyloid core consists of a short proteolytic fragment, which we have termed the core-amyloid fragment (CAF) and perhaps additional parts of the protein, such as the PKD domain. A highly O-glycosylated repeat (RPT) domain also derived from PMEL proteolysis associates with the amyloid and is necessary to establish the sheet-like morphology of the assemblies. Excluded from the aggregate is the regulatory N-terminus, which nevertheless must be linked in cis to the CAF in order to drive amyloid formation. The domain is then likely cleaved away immediately before, during, or immediately after the incorporation of a new CAF subunit into the nascent amyloid. We had previously identified a 21 amino acid long region, which mediates the regulatory activity of the N-terminus towards the CAF. However, many mutations in the respective segment caused misfolding and/or blocked PMEL export from the endoplasmic reticulum, leaving their phenotype hard to interpret. Here, we employ a saturating mutagenesis approach targeting the motif at single amino acid resolution. Our results confirm the critical nature of the PMEL N-terminal region and identify several residues essential for PMEL amyloidogenesis. |
| Databáze: | OpenAIRE |
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