Spectral analysis by XANES reveals that GPNMB influences the chemical composition of intact melanosomes.
Spectral analysis by XANES reveals that GPNMB influences the chemical composition of intact melanosomes.
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DOI：
10.1111/j.1755-148x.2010.00788.x
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发表时间：
2011-02
影响因子：
4.3
通讯作者：
Anderson MG
中科院分区：
文献类型：
--
作者：
Haraszti T;Trantow CM;Hedberg-Buenz A;Grunze M;Anderson MG
GPNMB is a unique melanosomal protein. Unlike many melanosomal proteins, GPNMB has not been associated with any forms of albinism and it is unclear whether GPNMB has any direct influence on melanosomes. Here, melanosomes from congenic strains of C57BL/6J mice mutant for Gpnmb are compared to strain-matched controls using standard transmission electron microscopy and synchrotron-based X-ray absorption near-edge structure analysis (XANES). Whereas electron microscopy did not detect any ultrastructural changes to melanosomes lacking functional GPNMB, XANES uncovered multiple spectral phenotypes. These results directly demonstrate that GPNMB influences the chemical composition of melanosomes, and more broadly illustrate the potential for using genetic approaches in combination with nano-imaging technologies to study organelle biology. Of the large number of proteins known to be present in melanosomes, the majority are not known to visibly influence melanosome appearance. It remains largely unknown what role, if any, most of these proteins may have in pigment cell biology. This work demonstrates an approach for discovering previously undetectable melanosomal phenotypes through a combined use of synchrotron-based spectromicroscopy and genetics. Specifically, we demonstrate that GPNMB influences the carbon absorption spectra of melanosomes. A similar strategy might also be applied to discover new features of a wide range of additional organelles important to human health and disease.
