Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL

Abstract 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, s...

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Autores principales:	Susan M. Mitchell, Morven Graham, Xinran Liu, Ralf M. Leonhardt
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/6fe1f58f16b744199acb7c25c9e073c8
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spelling	oai:doaj.org-article:6fe1f58f16b744199acb7c25c9e073c82021-12-02T18:15:45ZIdentification of critical amino acid residues in the regulatory N-terminal domain of PMEL10.1038/s41598-021-87259-y2045-2322https://doaj.org/article/6fe1f58f16b744199acb7c25c9e073c82021-04-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-87259-yhttps://doaj.org/toc/2045-2322Abstract 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.Susan M. MitchellMorven GrahamXinran LiuRalf M. LeonhardtNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-13 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Susan M. Mitchell Morven Graham Xinran Liu Ralf M. Leonhardt Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL
description	Abstract 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.
format	article
author	Susan M. Mitchell Morven Graham Xinran Liu Ralf M. Leonhardt
author_facet	Susan M. Mitchell Morven Graham Xinran Liu Ralf M. Leonhardt
author_sort	Susan M. Mitchell
title	Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL
title_short	Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL
title_full	Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL
title_fullStr	Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL
title_full_unstemmed	Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL
title_sort	identification of critical amino acid residues in the regulatory n-terminal domain of pmel
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/6fe1f58f16b744199acb7c25c9e073c8
work_keys_str_mv	AT susanmmitchell identificationofcriticalaminoacidresiduesintheregulatorynterminaldomainofpmel AT morvengraham identificationofcriticalaminoacidresiduesintheregulatorynterminaldomainofpmel AT xinranliu identificationofcriticalaminoacidresiduesintheregulatorynterminaldomainofpmel AT ralfmleonhardt identificationofcriticalaminoacidresiduesintheregulatorynterminaldomainofpmel
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Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL

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