1
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Kawahara R, Usami T, Arakawa S, Kamo H, Suzuki T, Komatsu R, Hara H, Niwa Y, Shimizu E, Dohmae N, Shimizu S, Simizu S. Biogenesis of fibrils requires C-mannosylation of PMEL. FEBS J 2023; 290:5373-5394. [PMID: 37552474 DOI: 10.1111/febs.16927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 07/22/2023] [Accepted: 08/07/2023] [Indexed: 08/09/2023]
Abstract
Premelanosome protein (PMEL), a melanocyte-specific glycoprotein, has an essential role in melanosome maturation, assembling amyloid fibrils for melanin deposition. PMEL undergoes several post-translational modifications, including N- and O-glycosylations, which are associated with proper melanosome development. C-mannosylation is a rare type of protein glycosylation at a tryptophan residue that might regulate the secretion and localization of proteins. PMEL has one putative C-mannosylation site in its core amyloid fragment (CAF); however, there is no report focusing on C-mannosylation of PMEL. To investigate this, we expressed recombinant PMEL in SK-MEL-28 human melanoma cells and purified the protein. Mass spectrometry analyses demonstrated that human PMEL is C-mannosylated at multiple tryptophan residues in its CAF and N-terminal fragment (NTF). In addition to the W153 or W156 residue (CAF), which lies in the consensus sequence for C-mannosylation, the W104 residue (NTF) was C-mannosylated without the consensus sequence. To determine the effects of the modifications, we deleted the PMEL gene by using CRISPR/Cas9 technology and re-expressed wild-type or C-mannosylation-defective mutants of PMEL, in which the C-mannosylated tryptophan was replaced with a phenylalanine residue (WF mutation), in SK-MEL-28 cells. Importantly, fibril-containing melanosomes were significantly decreased in W104F mutant PMEL-re-expressing cells compared with wild-type PMEL, observed using transmission electron microscopy. Furthermore, western blot and immunofluorescence analysis suggested that the W104F mutation may cause mild endoplasmic reticulumretention, possibly associated with early misfolding, and lysosomal misaggregation, thus reducing functional fibril formation. Our results demonstrate that C-mannosylation of PMEL is required for proper melanosome development by regulating PMEL-derived fibril formation.
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Affiliation(s)
- Ryota Kawahara
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan
| | - Tomoko Usami
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan
| | - Satoko Arakawa
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, Japan
- Research Core, Institute of Research, Tokyo Medical and Dental University, Japan
| | - Hiroki Kamo
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan
| | - Takehiro Suzuki
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Ryosuke Komatsu
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan
| | - Hiroyuki Hara
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, Tokyo, Japan
| | - Yuki Niwa
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan
| | - Erina Shimizu
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Shigeomi Shimizu
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, Japan
| | - Siro Simizu
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Japan
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2
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Buchanan JA, Varghese NR, Johnston CL, Sunde M. Functional Amyloids: Where Supramolecular Amyloid Assembly Controls Biological Activity or Generates New Functionality. J Mol Biol 2023; 435:167919. [PMID: 37330295 DOI: 10.1016/j.jmb.2022.167919] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/05/2022] [Accepted: 12/05/2022] [Indexed: 06/19/2023]
Abstract
Functional amyloids are a rapidly expanding class of fibrillar protein structures, with a core cross-β scaffold, where novel and advantageous biological function is generated by the assembly of the amyloid. The growing number of amyloid structures determined at high resolution reveal how this supramolecular template both accommodates a wide variety of amino acid sequences and also imposes selectivity on the assembly process. The amyloid fibril can no longer be considered a generic aggregate, even when associated with disease and loss of function. In functional amyloids the polymeric β-sheet rich structure provides multiple different examples of unique control mechanisms and structures that are finely tuned to deliver assembly or disassembly in response to physiological or environmental cues. Here we review the range of mechanisms at play in natural, functional amyloids, where tight control of amyloidogenicity is achieved by environmental triggers of conformational change, proteolytic generation of amyloidogenic fragments, or heteromeric seeding and amyloid fibril stability. In the amyloid fibril form, activity can be regulated by pH, ligand binding and higher order protofilament or fibril architectures that impact the arrangement of associated domains and amyloid stability. The growing understanding of the molecular basis for the control of structure and functionality delivered by natural amyloids in nearly all life forms should inform the development of therapies for amyloid-associated diseases and guide the design of innovative biomaterials.
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Affiliation(s)
- Jessica A Buchanan
- School of Medical Sciences and Sydney Nano, The University of Sydney, NSW 2006, Australia.
| | - Nikhil R Varghese
- School of Medical Sciences and Sydney Nano, The University of Sydney, NSW 2006, Australia.
| | - Caitlin L Johnston
- School of Medical Sciences and Sydney Nano, The University of Sydney, NSW 2006, Australia.
| | - Margaret Sunde
- School of Medical Sciences and Sydney Nano, The University of Sydney, NSW 2006, Australia.
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3
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Fernandes B, Cavaco-Paulo A, Matamá T. A Comprehensive Review of Mammalian Pigmentation: Paving the Way for Innovative Hair Colour-Changing Cosmetics. BIOLOGY 2023; 12:biology12020290. [PMID: 36829566 PMCID: PMC9953601 DOI: 10.3390/biology12020290] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/26/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023]
Abstract
The natural colour of hair shafts is formed at the bulb of hair follicles, and it is coupled to the hair growth cycle. Three critical processes must happen for efficient pigmentation: (1) melanosome biogenesis in neural crest-derived melanocytes, (2) the biochemical synthesis of melanins (melanogenesis) inside melanosomes, and (3) the transfer of melanin granules to surrounding pre-cortical keratinocytes for their incorporation into nascent hair fibres. All these steps are under complex genetic control. The array of natural hair colour shades are ascribed to polymorphisms in several pigmentary genes. A myriad of factors acting via autocrine, paracrine, and endocrine mechanisms also contributes for hair colour diversity. Given the enormous social and cosmetic importance attributed to hair colour, hair dyeing is today a common practice. Nonetheless, the adverse effects of the long-term usage of such cosmetic procedures demand the development of new methods for colour change. In this context, case reports of hair lightening, darkening and repigmentation as a side-effect of the therapeutic usage of many drugs substantiate the possibility to tune hair colour by interfering with the biology of follicular pigmentary units. By scrutinizing mammalian pigmentation, this review pinpoints key targetable processes for the development of innovative cosmetics that can safely change the hair colour from the inside out.
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Affiliation(s)
- Bruno Fernandes
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
| | - Artur Cavaco-Paulo
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
- LABBELS—Associate Laboratory, 4710-057 Braga, Portugal
- Correspondence: (A.C.-P.); (T.M.); Tel.: +351-253-604-409 (A.C.-P.); +351-253-601-599 (T.M.)
| | - Teresa Matamá
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
- LABBELS—Associate Laboratory, 4710-057 Braga, Portugal
- Correspondence: (A.C.-P.); (T.M.); Tel.: +351-253-604-409 (A.C.-P.); +351-253-601-599 (T.M.)
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4
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Surface-facilitated formation of polydopamine and its implications in melanogenesis. Colloids Surf B Biointerfaces 2023; 222:113068. [PMID: 36481509 DOI: 10.1016/j.colsurfb.2022.113068] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/25/2022] [Accepted: 11/30/2022] [Indexed: 12/02/2022]
Abstract
This manuscript examines influences of differently functionalized surfaces on the formation of solution-dispersed polydopamine (pDA). Glass vials functionalized with different functional groups provided a set of conditions with which the relationship between the area of active surface and the rate of pDA formation could be systematically studied. The results suggest that charged and polar surfaces accelerate pDA formation in solution, with the effect of -NH2 surfaces being exceptionally strong. In the vials, pDA formed as both forms of dispersions in solution and films at solid-liquid interface. Further analyses confirmed that both forms of pDA formed with -NH2 surfaces were chemically similar to conventional pDA synthesized without help of functional surfaces. Among short peptide-based amyloid fibers with defined surface functional groups, and those displaying lysines (-NH2) greatly accelerated the formation of pDA, consistent with the results of -NH2-functionalized vials. The results suggest that pDA formation may be facilitated by surface functional groups of solid-liquid interfaces, and have implications for the overlooked roles of amyloid fibers in biological melanogenesis.
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5
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Hassan MN, Nabi F, Khan AN, Hussain M, Siddiqui WA, Uversky VN, Khan RH. The amyloid state of proteins: A boon or bane? Int J Biol Macromol 2022; 200:593-617. [PMID: 35074333 DOI: 10.1016/j.ijbiomac.2022.01.115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 11/05/2022]
Abstract
Proteins and their aggregation is significant field of research due to their association with various conformational maladies including well-known neurodegenerative diseases like Alzheimer's (AD), Parkinson's (PD), and Huntington's (HD) diseases. Amyloids despite being given negative role for decades are also believed to play a functional role in bacteria to humans. In this review, we discuss both facets of amyloid. We have shed light on AD, which is one of the most common age-related neurodegenerative disease caused by accumulation of Aβ fibrils as extracellular senile plagues. We also discuss PD caused by the aggregation and deposition of α-synuclein in form of Lewy bodies and neurites. Other amyloid-associated diseases such as HD and amyotrophic lateral sclerosis (ALS) are also discussed. We have also reviewed functional amyloids that have various biological roles in both prokaryotes and eukaryotes that includes formation of biofilm and cell attachment in bacteria to hormone storage in humans, We discuss in detail the role of Curli fibrils' in biofilm formation, chaplins in cell attachment to peptide hormones, and Pre-Melansomal Protein (PMEL) roles. The disease-related and functional amyloids are compared with regard to their structural integrity, variation in regulation, and speed of forming aggregates and elucidate how amyloids have turned from foe to friend.
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Affiliation(s)
- Md Nadir Hassan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | - Faisal Nabi
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | - Asra Nasir Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | - Murtaza Hussain
- Department of Biochemistry, Aligarh Muslim University, Aligarh 202002, India
| | - Waseem A Siddiqui
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | - Vladimir N Uversky
- Protein Research Group, Institute for Biological Instrumentation of the Russian Academy of Sciences, 10 Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy 11 of Sciences", Pushchino, Moscow Region 142290, Russia; Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College 13 of Medicine, University of South Florida, Tampa, FL 33612, United States
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India.
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6
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sPmel17 Secreted by Ultraviolet B-Exposed Melanocytes Alters the Intercellular Adhesion of Keratinocytes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1856830. [PMID: 35186181 PMCID: PMC8853777 DOI: 10.1155/2022/1856830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 12/08/2021] [Accepted: 01/11/2022] [Indexed: 11/17/2022]
Abstract
Repigmentation of the skin in patients with vitiligo represents an intricate process in which the depigmented epidermis is replenished by functional melanocytes (MCs) that migrate from undamaged hair follicles and/or surrounding areas. We characterized whether MCs release a secreted form of Pmel17 (sPmel17) protein after exposure to UVB, thereby weakening the cell-cell adhesions of keratinocytes (KCs), which provides MCs the opportunity to migrate to areas devoid of MCs. At first, we examined the interactions of sPmel17 and FHL2 (four-and-a-half LIM domain protein 2) in KCs treated with the conditioned media (CM) from MCs exposed to UVB. The results showed that both the protein and mRNA levels of FHL2 were significantly upregulated in KCs treated with sPmel17-enriched CM from UVB-exposed MCs. We also found that there are physical interactions between sPmel17 and FHL2 as analyzed by reciprocal coimmunoprecipitation assays and double immunofluorescence staining. The CM from UVB-exposed MCs signaled KCs to remodel the actin cytoskeleton and reduce E-cadherin expression. However, the CM from UVB-exposed and Pmel17-silenced or from UVB-unexposed MCs failed to do this. To further determine the in situ distributions of sPmel17, FHL2, and E-cadherin, we examined the expression profiles of those proteins in the skin from healthy subjects and from depigmented or repigmented vitiligo using immunofluorescence and immunohistochemical staining. The results showed that the expression of sPmel17 was positively correlated with FHL2 but not to E-cadherin. The colocalization of FHL2 and sPmel17 was also observed in UVB-exposed mouse tail skin. Together, the upregulation of FHL2 in KCs requires stimulation by sPmel17 secreted from MCs and activation of the sPmel17-FHL2-E-cadherin axis offers a potential therapeutic target to expedite the repigmentation process in patients with vitiligo.
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7
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Faraj S, Kemp EH, Gawkrodger DJ. Patho-immunological mechanisms of vitiligo: the role of the innate and adaptive immunities and environmental stress factors. Clin Exp Immunol 2022; 207:27-43. [PMID: 35020865 PMCID: PMC8802175 DOI: 10.1093/cei/uxab002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 10/04/2021] [Accepted: 10/15/2021] [Indexed: 12/17/2022] Open
Abstract
Epidermal melanocyte loss in vitiligo, triggered by stresses ranging from trauma to emotional stress, chemical exposure or metabolite imbalance, to the unknown, can stimulate oxidative stress in pigment cells, which secrete damage-associated molecular patterns that then initiate innate immune responses. Antigen presentation to melanocytes leads to stimulation of autoreactive T-cell responses, with further targeting of pigment cells. Studies show a pathogenic basis for cellular stress, innate immune responses and adaptive immunity in vitiligo. Improved understanding of the aetiological mechanisms in vitiligo has already resulted in successful use of the Jak inhibitors in vitiligo. In this review, we outline the current understanding of the pathological mechanisms in vitiligo and locate loci to which therapeutic attack might be directed.
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Affiliation(s)
- Safa Faraj
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | | | - David John Gawkrodger
- Department of Infection, Immunology and Cardiovascular Disease, University of Sheffield, Sheffield, UK
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8
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Le L, Sirés-Campos J, Raposo G, Delevoye C, Marks MS. Melanosome biogenesis in the pigmentation of mammalian skin. Integr Comp Biol 2021; 61:1517-1545. [PMID: 34021746 DOI: 10.1093/icb/icab078] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Melanins, the main pigments of the skin and hair in mammals, are synthesized within membrane-bound organelles of melanocytes called melanosomes. Melanosome structure and function are determined by a cohort of resident transmembrane proteins, many of which are expressed only in pigment cells, that localize specifically to melanosomes. Defects in the genes that encode melanosome-specific proteins or components of the machinery required for their transport in and out of melanosomes underlie various forms of ocular or oculocutaneous albinism, characterized by hypopigmentation of the hair, skin and eyes and by visual impairment. We review major components of melanosomes, including the enzymes that catalyze steps in melanin synthesis from tyrosine precursors, solute transporters that allow these enzymes to function, and structural proteins that underlie melanosome shape and melanin deposition. We then review the molecular mechanisms by which these components are biosynthetically delivered to newly forming melanosomes-many of which are shared by other cell types that generate cell type-specific lysosome-related organelles. We also highlight unanswered questions that need to be addressed by future investigation.
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Affiliation(s)
- Linh Le
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA USA.,Department of Pathology & Laboratory Medicine and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA.,Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA USA
| | - Julia Sirés-Campos
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, Paris, 75005, France
| | - Graça Raposo
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, Paris, 75005, France
| | - Cédric Delevoye
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, Paris, 75005, France
| | - Michael S Marks
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA USA.,Department of Pathology & Laboratory Medicine and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
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9
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Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL. Sci Rep 2021; 11:7730. [PMID: 33833328 PMCID: PMC8032716 DOI: 10.1038/s41598-021-87259-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/26/2021] [Indexed: 01/22/2023] Open
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.
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10
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Hida T, Kamiya T, Kawakami A, Ogino J, Sohma H, Uhara H, Jimbow K. Elucidation of Melanogenesis Cascade for Identifying Pathophysiology and Therapeutic Approach of Pigmentary Disorders and Melanoma. Int J Mol Sci 2020; 21:ijms21176129. [PMID: 32854423 PMCID: PMC7503925 DOI: 10.3390/ijms21176129] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 08/22/2020] [Accepted: 08/22/2020] [Indexed: 12/15/2022] Open
Abstract
Melanogenesis is the biological and biochemical process of melanin and melanosome biosynthesis. Melanin is formed by enzymic reactions of tyrosinase family proteins that convert tyrosine to form brown-black eumelanin and yellow-red pheomelanin within melanosomal compartments in melanocytes, following the cascades of events interacting with a series of autocrine and paracrine signals. Fully melanized melanosomes are delivered to keratinocytes of the skin and hair. The symbiotic relation of a melanocyte and an associated pool of keratinocytes is called epidermal melanin unit (EMU). Microphthalmia-associated transcription factor (MITF) plays a vital role in melanocyte development and differentiation. MITF regulates expression of numerous pigmentation genes for promoting melanocyte differentiation, as well as fundamental genes for maintaining cell homeostasis. Diseases involving alterations of EMU show various forms of pigmentation phenotypes. This review introduces four major topics of melanogenesis cascade that include (1) melanocyte development and differentiation, (2) melanogenesis and intracellular trafficking for melanosome biosynthesis, (3) melanin pigmentation and pigment-type switching, and (4) development of a novel therapeutic approach for malignant melanoma by elucidation of melanogenesis cascade.
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Affiliation(s)
- Tokimasa Hida
- Department of Dermatology, Sapporo Medical University School of Medicine, Sapporo 060-8543, Hokkaido, Japan; (T.H.); (T.K.); (H.U.)
| | - Takafumi Kamiya
- Department of Dermatology, Sapporo Medical University School of Medicine, Sapporo 060-8543, Hokkaido, Japan; (T.H.); (T.K.); (H.U.)
| | - Akinori Kawakami
- Cutaneous Biology Research Center, Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA;
| | - Jiro Ogino
- Department of Pathology, JR Sapporo Hospital, Sapporo 060-0033, Hokkaido, Japan;
| | - Hitoshi Sohma
- Department of Biomedical Engineering, Sapporo Medical University School of Medicine, Sapporo 060-8556, Hokkaido, Japan;
| | - Hisashi Uhara
- Department of Dermatology, Sapporo Medical University School of Medicine, Sapporo 060-8543, Hokkaido, Japan; (T.H.); (T.K.); (H.U.)
| | - Kowichi Jimbow
- Institute of Dermatology & Cutaneous Sciences, Sapporo 060-0042, Hokkaido, Japan
- Correspondence: ; Tel.: +81-11-887-8266
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11
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Functional Mammalian Amyloids and Amyloid-Like Proteins. Life (Basel) 2020; 10:life10090156. [PMID: 32825636 PMCID: PMC7555005 DOI: 10.3390/life10090156] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/12/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
Amyloids are highly ordered fibrous cross-β protein aggregates that are notorious primarily because of association with a variety of incurable human and animal diseases (termed amyloidoses), including Alzheimer’s disease (AD), Parkinson’s disease (PD), type 2 diabetes (T2D), and prion diseases. Some amyloid-associated diseases, in particular T2D and AD, are widespread and affect hundreds of millions of people all over the world. However, recently it has become evident that many amyloids, termed “functional amyloids,” are involved in various activities that are beneficial to organisms. Functional amyloids were discovered in diverse taxa, ranging from bacteria to mammals. These amyloids are involved in vital biological functions such as long-term memory, storage of peptide hormones and scaffolding melanin polymerization in animals, substrate attachment, and biofilm formation in bacteria and fungi, etc. Thus, amyloids undoubtedly are playing important roles in biological and pathological processes. This review is focused on functional amyloids in mammals and summarizes approaches used for identifying new potentially amyloidogenic proteins and domains.
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12
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Lahola-Chomiak AA, Footz T, Nguyen-Phuoc K, Neil GJ, Fan B, Allen KF, Greenfield DS, Parrish RK, Linkroum K, Pasquale LR, Leonhardt RM, Ritch R, Javadiyan S, Craig JE, Allison WT, Lehmann OJ, Walter MA, Wiggs JL. Non-Synonymous variants in premelanosome protein (PMEL) cause ocular pigment dispersion and pigmentary glaucoma. Hum Mol Genet 2019; 28:1298-1311. [PMID: 30561643 DOI: 10.1093/hmg/ddy429] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/04/2018] [Accepted: 12/12/2018] [Indexed: 01/25/2023] Open
Abstract
Pigmentary glaucoma (PG) is a common glaucoma subtype that results from release of pigment from the iris, called pigment dispersion syndrome (PDS), and its deposition throughout the anterior chamber of the eye. Although PG has a substantial heritable component, no causative genes have yet been identified. We used whole exome sequencing of two independent pedigrees to identify two premelanosome protein (PMEL) variants associated with heritable PDS/PG. PMEL encodes a key component of the melanosome, the organelle essential for melanin synthesis, storage and transport. Targeted screening of PMEL in three independent cohorts (n = 394) identified seven additional PDS/PG-associated non-synonymous variants. Five of the nine variants exhibited defective processing of the PMEL protein. In addition, analysis of PDS/PG-associated PMEL variants expressed in HeLa cells revealed structural changes to pseudomelanosomes indicating altered amyloid fibril formation in five of the nine variants. Introduction of 11-base pair deletions to the homologous pmela in zebrafish by the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 method caused profound pigmentation defects and enlarged anterior segments in the eye, further supporting PMEL's role in ocular pigmentation and function. Taken together, these data support a model in which missense PMEL variants represent dominant negative mutations that impair the ability of PMEL to form functional amyloid fibrils. While PMEL mutations have previously been shown to cause pigmentation and ocular defects in animals, this research is the first report of mutations in PMEL causing human disease.
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Affiliation(s)
| | - Tim Footz
- Department of Medical Genetics, University of Alberta, Edmonton AB, Canada
| | - Kim Nguyen-Phuoc
- Department of Medical Genetics, University of Alberta, Edmonton AB, Canada
| | - Gavin J Neil
- Department of Biological Sciences, University of Alberta, Edmonton AB, Canada
| | - Baojian Fan
- Ocular Genomics Institute and Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Keri F Allen
- Ocular Genomics Institute and Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - David S Greenfield
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Palm Beach Gardens, FL, USA
| | - Richard K Parrish
- Anne Bates Leach Eye Hospital, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Kevin Linkroum
- Ocular Genomics Institute and Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Louis R Pasquale
- Ocular Genomics Institute and Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Ralf M Leonhardt
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Robert Ritch
- Einhorn Clinical Research Center, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Shari Javadiyan
- Department of Ophthalmology, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Jamie E Craig
- Department of Ophthalmology, Flinders Medical Centre, Adelaide, South Australia, Australia
| | - W T Allison
- Department of Medical Genetics, University of Alberta, Edmonton AB, Canada.,Department of Biological Sciences, University of Alberta, Edmonton AB, Canada
| | - Ordan J Lehmann
- Department of Medical Genetics, University of Alberta, Edmonton AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton AB, Canada
| | - Michael A Walter
- Department of Medical Genetics, University of Alberta, Edmonton AB, Canada
| | - Janey L Wiggs
- Ocular Genomics Institute and Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
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13
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Ginefra P, Filippi BGH, Donovan P, Bessonnard S, Constam DB. Compartment-Specific Biosensors Reveal a Complementary Subcellular Distribution of Bioactive Furin and PC7. Cell Rep 2019; 22:2176-2189. [PMID: 29466742 DOI: 10.1016/j.celrep.2018.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 12/13/2017] [Accepted: 01/31/2018] [Indexed: 12/21/2022] Open
Abstract
Furin trafficking, and that of related proprotein convertases (PCs), may regulate which substrates are accessible for endoproteolysis, but tools to directly test this hypothesis have been lacking. Here, we develop targeted biosensors that indicate Furin activity in endosomes is 10-fold less inhibited by decanoyl-RVKR-chloromethylketone and enriched >3-fold in endosomes compared to the trans-Golgi network (TGN). Endogenous PC7, which resists this inhibitor, was active in distinct vesicles. Only overexpressed PC7 activity reached the cell surface, endosomes, and the TGN. A PLC motif in the cytosolic tail of PC7 was dispensable for endosomal activity, but it was specifically required for TGN recycling and to rescue proActivin-A cleavage in Furin-depleted B16F1 melanoma cells. In sharp contrast, PC7 complemented Furin in cleaving Notch1 independently of PLC-mediated TGN access. Our study provides a proof in principle that compartment-specific biosensors can be used to gain insight into the regulation of PC trafficking and to map the tropism of PC-specific inhibitors.
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Affiliation(s)
- Pierpaolo Ginefra
- Ecole Polytechnique Fédérale de Lausanne (EPFL) SV ISREC, Station 19, 1015 Lausanne, Switzerland
| | - Bruno G H Filippi
- Ecole Polytechnique Fédérale de Lausanne (EPFL) SV ISREC, Station 19, 1015 Lausanne, Switzerland
| | - Prudence Donovan
- Ecole Polytechnique Fédérale de Lausanne (EPFL) SV ISREC, Station 19, 1015 Lausanne, Switzerland
| | - Sylvain Bessonnard
- Ecole Polytechnique Fédérale de Lausanne (EPFL) SV ISREC, Station 19, 1015 Lausanne, Switzerland
| | - Daniel B Constam
- Ecole Polytechnique Fédérale de Lausanne (EPFL) SV ISREC, Station 19, 1015 Lausanne, Switzerland.
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14
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Graham M, Tzika AC, Mitchell SM, Liu X, Leonhardt RM. Repeat domain-associated O-glycans govern PMEL fibrillar sheet architecture. Sci Rep 2019; 9:6101. [PMID: 30988362 PMCID: PMC6465243 DOI: 10.1038/s41598-019-42571-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/06/2019] [Indexed: 12/20/2022] Open
Abstract
PMEL is a pigment cell-specific protein that forms a functional amyloid matrix in melanosomes. The matrix consists of well-separated fibrillar sheets on which the pigment melanin is deposited. Using electron tomography, we demonstrate that this sheet architecture is governed by the PMEL repeat (RPT) domain, which associates with the amyloid as an accessory proteolytic fragment. Thus, the RPT domain is dispensable for amyloid formation as such but shapes the morphology of the matrix, probably in order to maximize the surface area available for pigment adsorption. Although the primary amino acid sequence of the RPT domain differs vastly among various vertebrates, we show that it is a functionally conserved, interchangeable module. RPT domains of all species are predicted to be very highly O-glycosylated, which is likely the common defining feature of this domain. O-glycosylation is indeed essential for RPT domain function and the establishment of the PMEL sheet architecture. Thus, O-glycosylation, not amino acid sequence, appears to be the major factor governing the characteristic PMEL amyloid morphology.
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Affiliation(s)
- Morven Graham
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06519, USA
| | - Athanasia C Tzika
- Department of Genetics & Evolution, Laboratory of Artificial & Natural Evolution (LANE), Sciences III Building, 1211, Geneva, 4, Switzerland
| | - Susan M Mitchell
- Department of Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, CT, 06519, USA
| | - Xinran Liu
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06519, USA
| | - Ralf M Leonhardt
- Department of Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, CT, 06519, USA.
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15
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Bissig C, Croisé P, Heiligenstein X, Hurbain I, Lenk GM, Kaufman E, Sannerud R, Annaert W, Meisler MH, Weisman LS, Raposo G, van Niel G. The PIKfyve complex regulates the early melanosome homeostasis required for physiological amyloid formation. J Cell Sci 2019; 132:jcs.229500. [PMID: 30709920 DOI: 10.1242/jcs.229500] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 01/14/2019] [Indexed: 12/23/2022] Open
Abstract
The metabolism of PI(3,5)P2 is regulated by the PIKfyve, VAC14 and FIG4 complex, mutations in which are associated with hypopigmentation in mice. These pigmentation defects indicate a key, but as yet unexplored, physiological relevance of this complex in the biogenesis of melanosomes. Here, we show that PIKfyve activity regulates formation of amyloid matrix composed of PMEL protein within the early endosomes in melanocytes, called stage I melanosomes. PIKfyve activity controls the membrane remodeling of stage I melanosomes, which regulates PMEL abundance, sorting and processing. PIKfyve activity also affects stage I melanosome kiss-and-run interactions with lysosomes, which are required for PMEL amyloidogenesis and the establishment of melanosome identity. Mechanistically, PIKfyve activity promotes both the formation of membrane tubules from stage I melanosomes and their release by modulating endosomal actin branching. Taken together, our data indicate that PIKfyve activity is a key regulator of the melanosomal import-export machinery that fine tunes the formation of functional amyloid fibrils in melanosomes and the maintenance of melanosome identity.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Christin Bissig
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Pauline Croisé
- IPNP, Institute of Psychiatry and Neuroscience of Paris, Hopital Saint-Anne, Université Paris Descartes, INSERM U894, 75014 Paris, France
| | - Xavier Heiligenstein
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Ilse Hurbain
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA
| | - Emily Kaufman
- Life Science Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Ragna Sannerud
- VIB Center for Brain & Disease Research, 3000 Leuven, Belgium.,KU Leuven, Department of Neurosciences, 3000 Leuven, Belgium
| | - Wim Annaert
- VIB Center for Brain & Disease Research, 3000 Leuven, Belgium.,KU Leuven, Department of Neurosciences, 3000 Leuven, Belgium
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA
| | - Lois S Weisman
- Life Science Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Graça Raposo
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Guillaume van Niel
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France .,IPNP, Institute of Psychiatry and Neuroscience of Paris, Hopital Saint-Anne, Université Paris Descartes, INSERM U894, 75014 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
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16
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Hasse S, Müller MC, Schallreuter KU, von Woedtke T. Stimulation of melanin synthesis in melanoma cells by cold plasma. Biol Chem 2018; 400:101-109. [DOI: 10.1515/hsz-2018-0223] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 10/30/2018] [Indexed: 11/15/2022]
Abstract
Abstract
Skin color is derived from epidermal melanocytes that contain specialized organelles in which melanin is formed. The formation of melanin is a well-orchestrated process, and reactive oxygen species (ROS) play a role in numerous enzymatic conversions, such as the reactions catalyzed by tyrosinase and tyrosine hydroxylase. Currently, there is ample evidence that cold plasma exerts biological effects on cells through the impact of ROS and reactive nitrogen species (RNS). Modulation of melanin biosynthesis by cold plasma has not yet been investigated. This study investigated melanin biosynthesis of human melanoma cell lines with different endogenous melanin contents (SK-Mel 28, G-361, FM-55-P and MNT-1) in response to cold plasma-derived reactive species. Initially, the distribution of melanosomes, via immunofluorescence, and the influence of microphthalmia-associated transcription factor (MiTF), as a key transcription factor, was investigated. In our experimental setup, all of the tested cell lines had an elevated melanin content after exposure to cold plasma. These promising results suggest a novel potential application of cold plasma for the regulation of melanogenesis and may be a useful tool for influencing skin color in the future.
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Affiliation(s)
- Sybille Hasse
- Department Plasma Life Science , Leibniz-Institute for Plasma Science and Technology (INP) , Felix-Hausdorff-Str. 2 , D-17489 Greifswald , Germany
| | - Marie-Christine Müller
- Department Plasma Life Science , Leibniz-Institute for Plasma Science and Technology (INP) , Felix-Hausdorff-Str. 2 , D-17489 Greifswald , Germany
| | - Karin Uta Schallreuter
- Institute for Pigmentary Disorders e.V. , Walther-Rathenau-Str. 49a , D-17489 Greifswald , Germany
| | - Thomas von Woedtke
- Department Plasma Life Science , Leibniz-Institute for Plasma Science and Technology (INP) , Felix-Hausdorff-Str. 2 , D-17489 Greifswald , Germany
- Institute for Hygiene and Environmental Medicine, University Medicine Greifswald , Ferdinand-Sauerbruch-Str. , D-17475 Greifswald , Germany
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17
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Vigneron N, Ferrari V, Van den Eynde BJ, Cresswell P, Leonhardt RM. Cytosolic Processing Governs TAP-Independent Presentation of a Critical Melanoma Antigen. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 201:1875-1888. [PMID: 30135181 PMCID: PMC6457910 DOI: 10.4049/jimmunol.1701479] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 07/26/2018] [Indexed: 12/30/2022]
Abstract
Cancer immunotherapy has been flourishing in recent years with remarkable clinical success. But as more patients are treated, a shadow is emerging that has haunted other cancer therapies: tumors develop resistance. Resistance is often caused by defects in the MHC class I Ag presentation pathway critical for CD8 T cell-mediated tumor clearance. TAP and tapasin, both key players in the pathway, are frequently downregulated in human cancers, correlating with poor patient survival. Reduced dependence on these factors may promote vaccine efficiency by limiting immune evasion. In this study, we demonstrate that PMEL209-217, a promising phase 3 trial-tested antimelanoma vaccine candidate, is robustly presented by various TAP- and/or tapasin-deficient cell lines. This striking characteristic may underlie its potency as a vaccine. Surprisingly, cytosolic proteasomes generate the peptide even for TAP-independent presentation, whereas tripeptidyl peptidase 2 (TPP2) efficiently degrades the epitope. Consequently, inhibiting TPP2 substantially boosts PMEL209-217 presentation, suggesting a possible strategy to improve the therapeutic efficacy of the vaccine.
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Affiliation(s)
- Nathalie Vigneron
- Ludwig Institute for Cancer Research, Brussels B-1200, Belgium
- de Duve Institute, University of Louvain, Brussels B-1200, Belgium
- Walloon Excellence in Life Sciences and Biotechnology, Brussels B-1200, Belgium
| | - Violette Ferrari
- Ludwig Institute for Cancer Research, Brussels B-1200, Belgium
- de Duve Institute, University of Louvain, Brussels B-1200, Belgium
- Walloon Excellence in Life Sciences and Biotechnology, Brussels B-1200, Belgium
| | - Benoît J Van den Eynde
- Ludwig Institute for Cancer Research, Brussels B-1200, Belgium;
- de Duve Institute, University of Louvain, Brussels B-1200, Belgium
- Walloon Excellence in Life Sciences and Biotechnology, Brussels B-1200, Belgium
| | - Peter Cresswell
- Department of Immunobiology, Yale University, New Haven, CT 06519; and
- Department of Cell Biology, Yale University, New Haven, CT 06519
| | - Ralf M Leonhardt
- Department of Immunobiology, Yale University, New Haven, CT 06519; and
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18
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Marijt KA, Blijleven L, Verdegaal EME, Kester MG, Kowalewski DJ, Rammensee HG, Stevanović S, Heemskerk MHM, van der Burg SH, van Hall T. Identification of non-mutated neoantigens presented by TAP-deficient tumors. J Exp Med 2018; 215:2325-2337. [PMID: 30115740 PMCID: PMC6122969 DOI: 10.1084/jem.20180577] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/30/2018] [Accepted: 07/10/2018] [Indexed: 12/29/2022] Open
Abstract
A hybrid forward-reversed immunological screen is performed to identify 16 novel HLA-A2 presented cancer antigens. These peptides are selectively presented by immune-escaped cancer cells with defects in the peptide transporter TAP. In contrast to mutated neoantigens, these “self” neoantigens are universally presented across different cancer types. Most T cell–based immunotherapies of cancer depend on intact antigen presentation by HLA class I molecules (HLA-I). However, defects in the antigen-processing machinery can cause downregulation of HLA-I, rendering tumor cells resistant to CD8+ T cells. Previously, we demonstrated that a unique category of cancer antigens is selectively presented by tumor cells deficient for the peptide transporter TAP, enabling a specific attack of such tumors without causing immunopathology in mouse models. With a novel combinatorial screening approach, we now identify 16 antigens of this category in humans. These HLA-A*02:01 presented peptides do not derive from the mutanome of cancers, but are of “self” origin and therefore constitute universal neoantigens. Indeed, CD8+ T cells specific for the leader peptide of the ubiquitously expressed LRPAP1 protein recognized TAP-deficient, HLA-Ilow lymphomas, melanomas, and renal and colon carcinomas, but not healthy counterparts. In contrast to personalized mutanome-targeted therapies, these conserved neoantigens and their cognate receptors can be exploited for immune-escaped cancers across diverse histological origins.
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Affiliation(s)
- Koen A Marijt
- Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands
| | - Laura Blijleven
- Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands
| | - Els M E Verdegaal
- Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands
| | - Michel G Kester
- Department of Hematology, Leiden University Medical Center, Leiden, Netherlands
| | - Daniel J Kowalewski
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Tübingen, Germany.,German Cancer Consortium, German Cancer Research Center, Tübingen, Germany
| | - Hans-Georg Rammensee
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Tübingen, Germany.,German Cancer Consortium, German Cancer Research Center, Tübingen, Germany
| | - Stefan Stevanović
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Tübingen, Germany.,German Cancer Consortium, German Cancer Research Center, Tübingen, Germany
| | | | - Sjoerd H van der Burg
- Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands
| | - Thorbald van Hall
- Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands
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19
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Serre C, Busuttil V, Botto JM. Intrinsic and extrinsic regulation of human skin melanogenesis and pigmentation. Int J Cosmet Sci 2018; 40:328-347. [PMID: 29752874 DOI: 10.1111/ics.12466] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 05/04/2018] [Indexed: 12/11/2022]
Abstract
In human skin, melanogenesis is a tightly regulated process. Indeed, several extracellular signals are transduced via dedicated signalling pathways and mostly converge to MITF, a transcription factor integrating upstream signalling and regulating downstream genes involved in the various inherent mechanisms modulating melanogenesis. The synthesis of melanin pigments occurs in melanocytes inside melanosomes where melanogenic enzymes (tyrosinase and related proteins) are addressed with the help of specific protein complexes. The melanosomes loaded with melanin are then transferred to keratinocytes. A more elaborate level of melanogenesis regulation comes into play via the action of non-coding RNAs (microRNAs, lncRNAs). Besides this canonical regulation, melanogenesis can also be modulated by other non-specific intrinsic pathways (hormonal environment, inflammation) and by extrinsic factors (solar irradiation such as ultraviolet irradiation, environmental pollution). We developed a bioinformatic interaction network gathering the multiple aspects of melanogenesis and skin pigmentation as a resource to better understand and study skin pigmentation biology.
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Affiliation(s)
- C Serre
- Global Skin Research Center, Ashland, 655, route du Pin Montard, Sophia Antipolis, 06904, France
| | - V Busuttil
- Global Skin Research Center, Ashland, 655, route du Pin Montard, Sophia Antipolis, 06904, France
| | - J-M Botto
- Global Skin Research Center, Ashland, 655, route du Pin Montard, Sophia Antipolis, 06904, France
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20
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Bergam P, Reisecker JM, Rakvács Z, Kucsma N, Raposo G, Szakacs G, van Niel G. ABCB6 Resides in Melanosomes and Regulates Early Steps of Melanogenesis Required for PMEL Amyloid Matrix Formation. J Mol Biol 2018; 430:3802-3818. [PMID: 29940187 DOI: 10.1016/j.jmb.2018.06.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/11/2018] [Accepted: 06/15/2018] [Indexed: 01/08/2023]
Abstract
Genetically inheritable pigmentation defects provide a unique opportunity to reveal the function of proteins contributing to melanogenesis. Dyschromatosis universalis hereditaria (DUH) is a rare pigmentary genodermatosis associated with mutations in the ABCB6 gene. Here we use optical and electron microscopy imaging combined with biochemical tools to investigate the localization and function of ABCB6 in pigment cells. We show that ABCB6 localizes to the membrane of early melanosomes and lysosomes of the human melanocytic cell line MNT-1. Depletion of ABCB6 by siRNA impaired PMEL amyloidogenesis in early melanosomes and induced aberrant accumulation of multilamellar aggregates in pigmented melanosomes. PMEL fibril formation and normal maturation of pigmented melanosomes could be restored by the overexpression of wild-type ABCB6 but not by variants containing an inactivating catalytic mutation (K629M) or the G579E DUH mutation. In line with the impairment of PMEL matrix formation in the absence of ABCB6, morphological analysis of the retinal pigment epithelium of ABCB6 knockout mice revealed a significant decrease of melanosome numbers. Our study extends the localization of ABCB6 to melanosomes, suggesting a potential link between the function of ABCB6 and the etiology of DUH to amyloid formation in pigment cells.
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Affiliation(s)
- Ptissam Bergam
- Institut Curie, PSL Research University, UMR144, Centre de Recherche, 26 rue d'Ulm, 75231 Paris, France; Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France; Cell and Tissue Imaging Core Facility PICT-IBiSA, Institut Curie, Paris, France
| | | | - Zsófia Rakvács
- Institute of Enzymology, Research Centre for National Sciences, HAS, Budapest 1117, Hungary
| | - Nóra Kucsma
- Institute of Enzymology, Research Centre for National Sciences, HAS, Budapest 1117, Hungary
| | - Graça Raposo
- Institut Curie, PSL Research University, UMR144, Centre de Recherche, 26 rue d'Ulm, 75231 Paris, France; Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France; Cell and Tissue Imaging Core Facility PICT-IBiSA, Institut Curie, Paris, France
| | - Gergely Szakacs
- Institute of Cancer Research, Medical University Vienna, Vienna, Austria; Institute of Enzymology, Research Centre for National Sciences, HAS, Budapest 1117, Hungary.
| | - Guillaume van Niel
- Institut Curie, PSL Research University, UMR144, Centre de Recherche, 26 rue d'Ulm, 75231 Paris, France; Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France; Cell and Tissue Imaging Core Facility PICT-IBiSA, Institut Curie, Paris, France; Center for Psychiatry and Neuroscience, Hopital Saint-Anne, Université Descartes, INSERM U894, Paris, France.
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21
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Homma T, Kageyama S, Nishikawa A, Nagata K. Melanosome degradation in epidermal keratinocytes related to lysosomal protease cathepsin V. Biochem Biophys Res Commun 2018; 500:339-343. [DOI: 10.1016/j.bbrc.2018.04.070] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 04/10/2018] [Indexed: 10/17/2022]
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22
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Jackson MP, Hewitt EW. Why are Functional Amyloids Non-Toxic in Humans? Biomolecules 2017; 7:biom7040071. [PMID: 28937655 PMCID: PMC5745454 DOI: 10.3390/biom7040071] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/18/2017] [Accepted: 09/20/2017] [Indexed: 12/26/2022] Open
Abstract
Amyloids were first identified in association with amyloidoses, human diseases in which proteins and peptides misfold into amyloid fibrils. Subsequent studies have identified an array of functional amyloid fibrils that perform physiological roles in humans. Given the potential for the production of toxic species in amyloid assembly reactions, it is remarkable that cells can produce these functional amyloids without suffering any obvious ill effect. Although the precise mechanisms are unclear, there are a number of ways in which amyloid toxicity may be prevented. These include regulating the level of the amyloidogenic peptides and proteins, minimising the production of prefibrillar oligomers in amyloid assembly reactions, sequestrating amyloids within membrane bound organelles, controlling amyloid assembly by other molecules, and disassembling the fibrils under physiological conditions. Crucially, a better understanding of how toxicity is avoided in the production of functional amyloids may provide insights into the prevention of amyloid toxicity in amyloidoses.
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Affiliation(s)
- Matthew P Jackson
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Eric W Hewitt
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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23
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McGlinchey RP, Lee JC. Reversing the amyloid trend: Mechanism of fibril assembly and dissolution of the repeat domain from a human functional amyloid. Isr J Chem 2017; 57:613-621. [PMID: 28993712 PMCID: PMC5630176 DOI: 10.1002/ijch.201600080] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Amyloids are traditionally observed in the context of disease. However, there is growing momentum that these structures can serve a beneficial role where the amyloid carries out a specific function. These so called 'functional amyloids' have all the structural hallmarks of disease-associated amyloids, raising the question as to what differentiates a well-behaved benign amyloid from a lethally destructive one. Here, we review our work on the repeat domain (RPT) from Pmel17, an important functional amyloid involved in melanin biosynthesis. Particularly, we focused our attention on the unique reversible aggregation-disaggregation process of RPT that is controlled strictly by solution pH. This pH dependence of RPT amyloid formation functions as a switch to control fibril assembly and maintains the benign nature that is associated with functional amyloids.
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Affiliation(s)
- Ryan P. McGlinchey
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Jennifer C. Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, U.S.A
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24
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Melanosomal formation of PMEL core amyloid is driven by aromatic residues. Sci Rep 2017; 7:44064. [PMID: 28272432 PMCID: PMC5341037 DOI: 10.1038/srep44064] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/01/2017] [Indexed: 12/05/2022] Open
Abstract
PMEL is a pigment cell protein that forms physiological amyloid in melanosomes. Many amyloids and/or their oligomeric precursors are toxic, causing or contributing to severe, incurable diseases including Alzheimer’s and prion diseases. Striking similarities in intracellular formation pathways between PMEL and various pathological amyloids including Aβ and PrPSc suggest PMEL is an excellent model system to study endocytic amyloid. Learning how PMEL fibrils assemble without apparent toxicity may help developing novel therapies for amyloid diseases. Here we identify the critical PMEL domain that forms the melanosomal amyloid core (CAF). An unbiased alanine-scanning screen covering the entire region combined with quantitative electron microscopy analysis of the full set of mutants uncovers numerous essential residues. Many of these rely on aromaticity for function suggesting a role for π-stacking in melanosomal amyloid assembly. Various mutants are defective in amyloid nucleation. This extensive data set informs the first structural model of the CAF and provides insights into how the melanosomal amyloid core forms.
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25
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Dogra P, Bhattacharya M, Mukhopadhyay S. pH-Responsive Mechanistic Switch Regulates the Formation of Dendritic and Fibrillar Nanostructures of a Functional Amyloid. J Phys Chem B 2017; 121:412-419. [DOI: 10.1021/acs.jpcb.6b11281] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Priyanka Dogra
- Centre
for Protein Science Design and Engineering, ‡Department of Biological Sciences, and §Department of
Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar 140306, Punjab, India
| | - Mily Bhattacharya
- Centre
for Protein Science Design and Engineering, ‡Department of Biological Sciences, and §Department of
Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar 140306, Punjab, India
| | - Samrat Mukhopadhyay
- Centre
for Protein Science Design and Engineering, ‡Department of Biological Sciences, and §Department of
Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar 140306, Punjab, India
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26
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Breydo L, Redington JM, Uversky VN. Effects of Intrinsic and Extrinsic Factors on Aggregation of Physiologically Important Intrinsically Disordered Proteins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 329:145-185. [PMID: 28109327 DOI: 10.1016/bs.ircmb.2016.08.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Misfolding and aggregation of proteins and peptides play an important role in a number of diseases as well as in many physiological processes. Many of the proteins that misfold and aggregate in vivo are intrinsically disordered. Protein aggregation is a complex multistep process, and aggregates can significantly differ in morphology, structure, stability, cytotoxicity, and self-propagation ability. The aggregation process is influenced by both intrinsic (e.g., mutations and expression levels) and extrinsic (e.g., polypeptide chain truncation, macromolecular crowding, posttranslational modifications, as well as interaction with metal ions, other small molecules, lipid membranes, and chaperons) factors. This review examines the effect of a variety of these factors on aggregation of physiologically important intrinsically disordered proteins.
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Affiliation(s)
- L Breydo
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.
| | - J M Redington
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - V N Uversky
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States; Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
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27
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Bissig C, Rochin L, van Niel G. PMEL Amyloid Fibril Formation: The Bright Steps of Pigmentation. Int J Mol Sci 2016; 17:ijms17091438. [PMID: 27589732 PMCID: PMC5037717 DOI: 10.3390/ijms17091438] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 08/12/2016] [Accepted: 08/22/2016] [Indexed: 02/06/2023] Open
Abstract
In pigment cells, melanin synthesis takes place in specialized organelles, called melanosomes. The biogenesis and maturation of melanosomes is initiated by an unpigmented step that takes place prior to the initiation of melanin synthesis and leads to the formation of luminal fibrils deriving from the pigment cell-specific pre-melanosomal protein (PMEL). In the lumen of melanosomes, PMEL fibrils optimize sequestration and condensation of the pigment melanin. Interestingly, PMEL fibrils have been described to adopt a typical amyloid-like structure. In contrast to pathological amyloids often associated with neurodegenerative diseases, PMEL fibrils represent an emergent category of physiological amyloids due to their beneficial cellular functions. The formation of PMEL fibrils within melanosomes is tightly regulated by diverse mechanisms, such as PMEL traffic, cleavage and sorting. These mechanisms revealed increasing analogies between the formation of physiological PMEL fibrils and pathological amyloid fibrils. In this review we summarize the known mechanisms of PMEL fibrillation and discuss how the recent understanding of physiological PMEL amyloid formation may help to shed light on processes involved in pathological amyloid formation.
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Affiliation(s)
- Christin Bissig
- Institut Curie, Paris Sciences et Lettres Research University, UMR144, Centre de Recherche, 26 rue d'ULM, Paris F-75231, France.
- Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France.
| | - Leila Rochin
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK.
| | - Guillaume van Niel
- Institut Curie, Paris Sciences et Lettres Research University, UMR144, Centre de Recherche, 26 rue d'ULM, Paris F-75231, France.
- Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France.
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28
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van Niel G. Study of Exosomes Shed New Light on Physiology of Amyloidogenesis. Cell Mol Neurobiol 2016; 36:327-42. [DOI: 10.1007/s10571-016-0357-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 02/27/2016] [Indexed: 12/18/2022]
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Louros NN, Baltoumas FA, Hamodrakas SJ, Iconomidou VA. A β-solenoid model of the Pmel17 repeat domain: insights to the formation of functional amyloid fibrils. J Comput Aided Mol Des 2016; 30:153-64. [PMID: 26754844 DOI: 10.1007/s10822-015-9892-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/21/2015] [Indexed: 10/22/2022]
Abstract
Pmel17 is a multidomain protein involved in biosynthesis of melanin. This process is facilitated by the formation of Pmel17 amyloid fibrils that serve as a scaffold, important for pigment deposition in melanosomes. A specific luminal domain of human Pmel17, containing 10 tandem imperfect repeats, designated as repeat domain (RPT), forms amyloid fibrils in a pH-controlled mechanism in vitro and has been proposed to be essential for the formation of the fibrillar matrix. Currently, no three-dimensional structure has been resolved for the RPT domain of Pmel17. Here, we examine the structure of the RPT domain by performing sequence threading. The resulting model was subjected to energy minimization and validated through extensive molecular dynamics simulations. Structural analysis indicated that the RPT model exhibits several distinct properties of β-solenoid structures, which have been proposed to be polymerizing components of amyloid fibrils. The derived model is stabilized by an extensive network of hydrogen bonds generated by stacking of highly conserved polar residues of the RPT domain. Furthermore, the key role of invariant glutamate residues is proposed, supporting a pH-dependent mechanism for RPT domain assembly. Conclusively, our work attempts to provide structural insights into the RPT domain structure and to elucidate its contribution to Pmel17 amyloid fibril formation.
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Affiliation(s)
- Nikolaos N Louros
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, 157 01, Athens, Greece
| | - Fotis A Baltoumas
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, 157 01, Athens, Greece
| | - Stavros J Hamodrakas
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, 157 01, Athens, Greece
| | - Vassiliki A Iconomidou
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, 157 01, Athens, Greece.
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30
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Ho T, Watt B, Spruce LA, Seeholzer SH, Marks MS. The Kringle-like Domain Facilitates Post-endoplasmic Reticulum Changes to Premelanosome Protein (PMEL) Oligomerization and Disulfide Bond Configuration and Promotes Amyloid Formation. J Biol Chem 2015; 291:3595-612. [PMID: 26694611 DOI: 10.1074/jbc.m115.692442] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Indexed: 11/06/2022] Open
Abstract
The formation of functional amyloid must be carefully regulated to prevent the accumulation of potentially toxic products. Premelanosome protein (PMEL) forms non-toxic functional amyloid fibrils that assemble into sheets upon which melanins ultimately are deposited within the melanosomes of pigment cells. PMEL is synthesized in the endoplasmic reticulum but forms amyloid only within post-Golgi melanosome precursors; thus, PMEL must traverse the secretory pathway in a non-amyloid form. Here, we identified two pre-amyloid PMEL intermediates that likely regulate the timing of fibril formation. Analyses by non-reducing SDS-PAGE, size exclusion chromatography, and sedimentation velocity revealed two native high Mr disulfide-bonded species that contain Golgi-modified forms of PMEL. These species correspond to disulfide bond-containing dimeric and monomeric PMEL isoforms that contain no other proteins as judged by two-dimensional PAGE of metabolically labeled/immunoprecipitated PMEL and by mass spectrometry of affinity-purified complexes. Metabolic pulse-chase analyses, small molecule inhibitor treatments, and evaluation of site-directed mutants suggest that the PMEL dimer forms around the time of endoplasmic reticulum exit and is resolved by disulfide bond rearrangement into a monomeric form within the late Golgi or a post-Golgi compartment. Mutagenesis of individual cysteine residues within the non-amyloid cysteine-rich Kringle-like domain stabilizes the disulfide-bonded dimer and impairs fibril formation as determined by electron microscopy. Our data show that the Kringle-like domain facilitates the resolution of disulfide-bonded PMEL dimers and promotes PMEL functional amyloid formation, thereby suggesting that PMEL dimers must be resolved to monomers to generate functional amyloid fibrils.
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Affiliation(s)
- Tina Ho
- From the Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104 and the Cell and Molecular Biology Graduate Group, the Department of Pathology and Laboratory Medicine, and
| | - Brenda Watt
- From the Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104 and the Cell and Molecular Biology Graduate Group, the Department of Pathology and Laboratory Medicine, and
| | - Lynn A Spruce
- From the Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104 and
| | - Steven H Seeholzer
- From the Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104 and
| | - Michael S Marks
- From the Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104 and the Cell and Molecular Biology Graduate Group, the Department of Pathology and Laboratory Medicine, and the Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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31
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Shi F, Xu Z, Chen H, Wang X, Cui J, Zhang P, Zhang P, Xie X. A Monoclonal Antibody Against PMEL. Monoclon Antib Immunodiagn Immunother 2014; 33:354-60. [PMID: 25118787 DOI: 10.1089/mab.2013.0094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Fangyuan Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi'an, China
| | - Zhenjie Xu
- Department of Translational Medicine, Institute of Integrated Medical Information, Xi'an, China
| | - Hongdong Chen
- Department of Translational Medicine, Institute of Integrated Medical Information, Xi'an, China
| | - Xin Wang
- Central Laboratory, Shaanxi Provincial People's Hospital, Third Affiliated Hospital of the School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Jihong Cui
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi'an, China
| | - Ping Zhang
- Department of Translational Medicine, Institute of Integrated Medical Information, Xi'an, China
| | - Ping Zhang
- Department of Dermatology, The General Hospital of the Air Force, Beijing, China
| | - Xin Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi'an, China
- Department of Translational Medicine, Institute of Integrated Medical Information, Xi'an, China
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32
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Leonhardt RM, Abrahimi P, Mitchell SM, Cresswell P. Three tapasin docking sites in TAP cooperate to facilitate transporter stabilization and heterodimerization. THE JOURNAL OF IMMUNOLOGY 2014; 192:2480-94. [PMID: 24501197 DOI: 10.4049/jimmunol.1302637] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The TAP translocates peptide Ags into the lumen of the endoplasmic reticulum for loading onto MHC class I molecules. MHC class I acquires its peptide cargo in the peptide loading complex, an oligomeric complex that the chaperone tapasin organizes by bridging TAP to MHC class I and recruiting accessory molecules such as ERp57 and calreticulin. Three tapasin binding sites on TAP have been described, two of which are located in the N-terminal domains of TAP1 and TAP2. The third binding site is present in the core transmembrane (TM) domain of TAP1 and is used only by the unassembled subunits. Tapasin is required to promote TAP stability, but through which binding site(s) it is acting is unknown. In particular, the role of tapasin binding to the core TM domain of TAP1 single chains is mysterious because this interaction is lost upon TAP2 association. In this study, we map the respective binding site in TAP1 to the polar face of the amphipathic TM helix TM9 and identify key residues that are essential to establish the interaction. We find that this interaction is dispensable for the peptide transport function but essential to achieve full stability of human TAP1. The interaction is also required for proper heterodimerization of the transporter. Based on similar results obtained using TAP mutants that lack tapasin binding to either N-terminal domain, we conclude that all three tapasin-binding sites in TAP cooperate to achieve high transporter stability and efficient heterodimerization.
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33
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BACE2 processes PMEL to form the melanosome amyloid matrix in pigment cells. Proc Natl Acad Sci U S A 2013; 110:10658-63. [PMID: 23754390 DOI: 10.1073/pnas.1220748110] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Amyloids are often associated with pathologic processes such as in Alzheimer's disease (AD), but can also underlie physiological processes such as pigmentation. Formation of pathological and functional amyloidogenic substrates can require precursor processing by proteases, as exemplified by the generation of Aβ peptide from amyloid precursor protein (APP) by beta-site APP cleaving enzyme (BACE)1 and γ-secretase. Proteolytic processing of the pigment cell-specific Melanocyte Protein (PMEL) is also required to form functional amyloid fibrils during melanogenesis, but the enzymes involved are incompletely characterized. Here we show that the BACE1 homologue BACE2 processes PMEL to generate functional amyloids. BACE2 is highly expressed in pigment cells and Bace2(-/-) but not Bace1(-/-) mice display coat color defects, implying a specific role for BACE2 during melanogenesis. By using biochemical and morphological analyses, combined with RNA silencing, pharmacologic inhibition, and BACE2 overexpression in a human melanocytic cell line, we show that BACE2 cleaves the integral membrane form of PMEL within the juxtamembrane domain, releasing the PMEL luminal domain into endosomal precursors for the formation of amyloid fibrils and downstream melanosome morphogenesis. These studies identify an amyloidogenic substrate of BACE2, reveal an important physiological role for BACE2 in pigmentation, and highlight analogies in the generation of PMEL-derived functional amyloids and APP-derived pathological amyloids.
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34
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Theos AC, Watt B, Harper DC, Janczura KJ, Theos SC, Herman KE, Marks MS. The PKD domain distinguishes the trafficking and amyloidogenic properties of the pigment cell protein PMEL and its homologue GPNMB. Pigment Cell Melanoma Res 2013; 26:470-86. [PMID: 23452376 DOI: 10.1111/pcmr.12084] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 02/26/2013] [Indexed: 11/29/2022]
Abstract
Proteolytic fragments of the pigment cell-specific glycoprotein, PMEL, form the amyloid fibrillar matrix underlying melanins in melanosomes. The fibrils form within multivesicular endosomes to which PMEL is selectively sorted and that serve as melanosome precursors. GPNMB is a tissue-restricted glycoprotein with substantial sequence homology to PMEL, but no known function, and was proposed to localize to non-fibrillar domains of distinct melanosome subcompartments in melanocytes. Here we confirm that GPNMB localizes to compartments distinct from the PMEL-containing multivesicular premelanosomes or late endosomes in melanocytes and HeLa cells, respectively, and is largely absent from fibrils. Using domain swapping, the unique PMEL localization is ascribed to its polycystic kidney disease (PKD) domain, whereas the homologous PKD domain of GPNMB lacks apparent sorting function. The difference likely reflects extensive modification of the GPNMB PKD domain by N-glycosylation, nullifying its sorting function. These results reveal the molecular basis for the distinct trafficking and morphogenetic properties of PMEL and GPNMB and support a deterministic function of the PMEL PKD domain in both protein sorting and amyloidogenesis.
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Affiliation(s)
- Alexander C Theos
- Department of Pathology & Laboratory Medicine and Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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35
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Watt B, van Niel G, Raposo G, Marks MS. PMEL: a pigment cell-specific model for functional amyloid formation. Pigment Cell Melanoma Res 2013; 26:300-15. [PMID: 23350640 DOI: 10.1111/pcmr.12067] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 01/15/2013] [Indexed: 12/15/2022]
Abstract
PMEL is a pigment cell-specific protein responsible for the formation of fibrillar sheets within the pigment organelle, the melanosome. The fibrillar sheets serve as a template upon which melanins polymerize as they are synthesized. The PMEL fibrils are required for optimal pigment cell function, as animals that either lack PMEL expression or express mutant PMEL variants show varying degrees of hypopigmentation and pigment cell inviability. The PMEL fibrils have biophysical properties of amyloid, a protein fold that is frequently associated with neurodegenerative and other diseases. However, PMEL is one of a growing number of non-pathogenic amyloid proteins that contribute to the function of the cell and/or organism that produces them. Understanding how PMEL generates amyloid in a non-pathogenic manner might provide insights into how to avoid toxicity due to pathological amyloid formation. In this review, we summarize and reconcile data concerning the fate of PMEL from its site of synthesis in the endoplasmic reticulum to newly formed melanosomes and the role of distinct PMEL subdomains in trafficking and amyloid fibril formation. We then discuss how its progression through the secretory pathway into the endosomal system might allow for the regulated and non-toxic conversion of PMEL into an ordered amyloid polymer.
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Affiliation(s)
- Brenda Watt
- Department of Pathology and Laboratory Medicine, Department of Physiology, and Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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36
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Leonhardt RM, Vigneron N, Hee JS, Graham M, Cresswell P. Critical residues in the PMEL/Pmel17 N-terminus direct the hierarchical assembly of melanosomal fibrils. Mol Biol Cell 2013; 24:964-81. [PMID: 23389629 PMCID: PMC3608505 DOI: 10.1091/mbc.e12-10-0742] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Asp-73, Pro-75, Trp-153, and Trp-160 are essential residues in the PMEL NTR that are required for functional fibril formation. The NTR is necessary in cis to drive the downstream PKD into an amyloid core matrix, which subsequently incorporates and stabilizes the RPT domain–containing, MαC fibril–associated fragment. PMEL (also called Pmel17 or gp100) is a melanocyte/melanoma-specific glycoprotein that plays a critical role in melanosome development by forming a fibrillar amyloid matrix in the organelle for melanin deposition. Although ultimately not a component of mature fibrils, the PMEL N-terminal region (NTR) is essential for their formation. By mutational analysis we establish a high-resolution map of this domain in which sequence elements and functionally critical residues are assigned. We show that the NTR functions in cis to drive the aggregation of the downstream polycystic kidney disease (PKD) domain into a melanosomal core matrix. This is essential to promote in trans the stabilization and terminal proteolytic maturation of the repeat (RPT) domain–containing MαC units, precursors of the second fibrillogenic fragment. We conclude that during melanosome biogenesis the NTR controls the hierarchical assembly of melanosomal fibrils.
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Affiliation(s)
- Ralf M Leonhardt
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.
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37
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Molecular basis of albinism in India: evaluation of seven potential candidate genes and some new findings. Gene 2012; 511:470-4. [PMID: 23010199 DOI: 10.1016/j.gene.2012.09.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 09/06/2012] [Accepted: 09/06/2012] [Indexed: 11/21/2022]
Abstract
Albinism represents a group of genetic disorders with a broad spectrum of hypopigmentary phenotypes dependent on the genetic background of the patients. Oculocutaneous albinism (OCA) patients have little or no pigment in their eyes, skin and hair, whereas ocular albinism (OA) primarily presents the ocular symptoms, and the skin and hair color may vary from near normal to very fair. Mutations in genes directly or indirectly regulating melanin production are responsible for different forms of albinism with overlapping clinical features. In this study, 27 albinistic individuals from 24 families were screened for causal variants by a PCR-sequencing based approach. TYR, OCA2, TYRP1, SLC45A2, SLC24A5, TYRP2 and SILV were selected as candidate genes. We identified 5 TYR and 3 OCA2 mutations, majority in homozygous state, in 8 unrelated patients including a case of autosomal recessive ocular albinism (AROA). A homozygous 4-nucleotide novel insertion in SLC24A5 was detected in a person showing with extreme cutaneous hypopigmentation. A potential causal variant was identified in the TYRP2 gene in a single patient. Haplotype analyses in the patients carrying homozygous mutations in the classical OCA genes suggested founder effect. This is the first report of an Indian AROA patient harboring a mutation in OCA2. Our results also reveal for the first time that mutations in SLC24A5 could contribute to extreme hypopigmentation in humans.
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Sitaram A, Marks MS. Mechanisms of protein delivery to melanosomes in pigment cells. Physiology (Bethesda) 2012; 27:85-99. [PMID: 22505665 DOI: 10.1152/physiol.00043.2011] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vertebrate pigment cells in the eye and skin are useful models for cell types that use specialized endosomal trafficking pathways to partition cargo proteins to unique lysosome-related organelles such as melanosomes. This review describes current models of protein trafficking required for melanosome biogenesis in mammalian melanocytes.
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Affiliation(s)
- Anand Sitaram
- Cell and Molecular Biology Graduate Group, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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39
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Chen Y, Chalouni C, Tan C, Clark R, Venook R, Ohri R, Raab H, Firestein R, Mallet W, Polakis P. The melanosomal protein PMEL17 as a target for antibody drug conjugate therapy in melanoma. J Biol Chem 2012; 287:24082-91. [PMID: 22613716 DOI: 10.1074/jbc.m112.361485] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Melanocytes uniquely express specialized genes required for pigment formation, some of which are maintained following their transformation to melanoma. Here we exploit this property to selectively target melanoma with an antibody drug conjugate (ADC) specific to PMEL17, the product of the SILV pigment-forming gene. We describe new PMEL17 antibodies that detect the endogenous protein. These antibodies help define the secretory fate of PMEL17 and demonstrate its utility as an ADC target. Although newly synthesized PMEL17 is ultimately routed to the melanosome, we find substantial amounts accessible to our antibodies at the cell surface that undergo internalization and routing to a LAMP1-enriched, lysosome-related organelle. Accordingly, an ADC reactive with PMEL17 exhibits target-dependent tumor cell killing in vitro and in vivo.
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Affiliation(s)
- Youjun Chen
- Department of Research Oncology, Genentech, South San Francisco, California 94080, USA
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40
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Whelly S, Johnson S, Powell J, Borchardt C, Hastert MC, Cornwall GA. Nonpathological extracellular amyloid is present during normal epididymal sperm maturation. PLoS One 2012; 7:e36394. [PMID: 22570708 PMCID: PMC3343081 DOI: 10.1371/journal.pone.0036394] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 04/06/2012] [Indexed: 11/19/2022] Open
Abstract
Amyloids are aggregated proteins characterized by a specific cross-β-sheet structure and are typically associated with neurodegenerative diseases including Alzheimer's disease. Recently, however, several nonpathological amyloids have been found in intracellular organelles of normal mammalian tissues suggesting that amyloid may also carry out biological functions. We previously have shown that the epididymal cystatin CRES (cystatin-related epididymal spermatogenic), cst8, a reproductive-specific member of the cystatin superfamily of cysteine protease inhibitors, forms amyloid in vitro suggesting that CRES amyloid may also form in vivo within the epididymal lumen. Here we show that amyloid structures containing CRES are a component of the normal mouse epididymal lumen without any apparent cytotoxic effects on spermatozoa and that these structures change along the length of the tubule. These studies suggest the presence of a functional amyloid structure that may carry out roles in sperm maturation or maintenance of the luminal milieu and which itself may undergo maturational changes along the epididymis. In contrast to previous examples of functional amyloid which were intracellular, our studies now show that nonpathological/functional amyloid can also be extracellular. The presence of an extracellular and nonpathological amyloid in the epididymis suggests that similar amyloid structures may be present in other organ systems and may carry out distinctive tissue-specific functions.
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Affiliation(s)
- Sandra Whelly
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Seethal Johnson
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Jonathan Powell
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Clinton Borchardt
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
| | - Mary Catherine Hastert
- Department of Biology, Imaging Center, Texas Tech University, Lubbock, Texas, United States of America
| | - Gail A. Cornwall
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America
- * E-mail:
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41
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Watt B, Tenza D, Lemmon MA, Kerje S, Raposo G, Andersson L, Marks MS. Mutations in or near the transmembrane domain alter PMEL amyloid formation from functional to pathogenic. PLoS Genet 2011; 7:e1002286. [PMID: 21949659 PMCID: PMC3174235 DOI: 10.1371/journal.pgen.1002286] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 07/28/2011] [Indexed: 11/18/2022] Open
Abstract
PMEL is a pigment cell-specific protein that forms physiological amyloid fibrils upon which melanins ultimately deposit in the lumen of the pigment organelle, the melanosome. Whereas hypomorphic PMEL mutations in several species result in a mild pigment dilution that is inherited in a recessive manner, PMEL alleles found in the Dominant white (DW) chicken and Silver horse (HoSi)--which bear mutations that alter the PMEL transmembrane domain (TMD) and that are thus outside the amyloid core--are associated with a striking loss of pigmentation that is inherited in a dominant fashion. Here we show that the DW and HoSi mutations alter PMEL TMD oligomerization and/or association with membranes, with consequent formation of aberrantly packed fibrils. The aberrant fibrils are associated with a loss of pigmentation in cultured melanocytes, suggesting that they inhibit melanin production and/or melanosome integrity. A secondary mutation in the Smoky chicken, which reverts the dominant DW phenotype, prevents the accumulation of PMEL in fibrillogenic compartments and thus averts DW-associated pigment loss; a secondary mutation found in the Dun chicken likely dampens a HoSi-like dominant mutation in a similar manner. We propose that the DW and HoSi mutations alter the normally benign amyloid to a pathogenic form that antagonizes melanosome function, and that the secondary mutations found in the Smoky and Dun chickens revert or dampen pathogenicity by functioning as null alleles, thus preventing the formation of aberrant fibrils. We speculate that PMEL mutations can model the conversion between physiological and pathological amyloid.
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Affiliation(s)
- Brenda Watt
- Department of Pathology and Laboratory Medicine and Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Danièle Tenza
- Institut Curie, Centre de Recherche, Paris, France
- CNRS, UMR-144, Paris, France
| | - Mark A. Lemmon
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Susanne Kerje
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Graça Raposo
- Institut Curie, Centre de Recherche, Paris, France
- CNRS, UMR-144, Paris, France
| | - Leif Andersson
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Michael S. Marks
- Department of Pathology and Laboratory Medicine and Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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