Journal article
Support and challenges to the melanosomal casing model based on nanoscale distribution of metals within iris melanosomes detected by X-ray fluorescence analysis
Pigment cell and melanoma research, Vol.27(5), pp.831-834
09/2014
DOI: 10.1111/pcmr.12278
PMCID: PMC4150745
PMID: 24903463
Abstract
Melanin within melanosomes exists as eumelanin or pheomelanin. Distributions of these melanins have been studied extensively within tissues, but less often within individual melanosomes. Here, we apply X-ray fluorescence analysis with synchrotron radiation to survey the nanoscale distribution of metals within purified melanosomes of mice. The study allows a discovery-based characterization of melanosomal metals, and, because Cu is specifically associated with eumelanin, a hypothesis-based test of the “casing model” predicting that melanosomes contain a pheomelanin core surrounded by a eumelanin shell. Analysis of Cu, Ca, and Zn shows variable concentrations and distributions, with Ca/Zn highly correlated, and at least three discrete patterns for the distribution of Cu vs. Ca/Zn in different melanosomes – including one with a Cu-rich shell surrounding a Ca/Zn-rich core. Thus, the results support predictions of the casing model, but also suggest that in at least some tissues and genetic contexts, other arrangements of melanin may co-exist.
Details
- Title: Subtitle
- Support and challenges to the melanosomal casing model based on nanoscale distribution of metals within iris melanosomes detected by X-ray fluorescence analysis
- Creators
- Thomas Gorniak - Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyTamás Haraszti - Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, GermanyHeikki Suhonen - ESRF, 6 rue Jules Horowitz, BP 220, F-38043 Grenoble Cedex, FranceYang Yang - Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyAdam Hedberg-Buenz - Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA 52242, USADemelza Koehn - Center for the Prevention and Treatment of Visual Loss, Iowa City Veterans Affairs (VA) Health Care System, Iowa City, IA 52246, USARuth Heine - Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyMichael Grunze - Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyAxel Rosenhahn - Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyMichael G Anderson - Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA 52242, USA
- Resource Type
- Journal article
- Publication Details
- Pigment cell and melanoma research, Vol.27(5), pp.831-834
- DOI
- 10.1111/pcmr.12278
- PMID
- 24903463
- PMCID
- PMC4150745
- NLM abbreviation
- Pigment Cell Melanoma Res
- ISSN
- 1755-1471
- eISSN
- 1755-148X
- Grant note
- DOI: 10.13039/100000053, name: National Eye Institute, award: EY017673; name: Virtual Institute, award: VH-VI-403
- Language
- English
- Date published
- 09/2014
- Academic Unit
- Molecular Physiology and Biophysics; Ophthalmology and Visual Sciences
- Record Identifier
- 9984025465502771
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