Proteomic analysis on the regulation of DOPA-melanin synthesis in Talaromyces marneffei

Background: Yeast form of T.marneffei can produce DOPA-melanin which perform an important role in the pathogen surviving in macrophage. So far, the proteomic associated with melanin synthesis remain unclearly in T.marneffei. Methods: The whole yeast cell proteins were extracted from T.marneffei cultured with or without LDOPA. Using two-dimensional gel electrophoresis combined with MALDI-TOF mass spectrometry, distinguished proteins were identified between T.marneffei cultured with or without L-DOPA. Furthermore, geldanamycin were used to assess the inhibition effect on T.marneffei melanin production in vitro. Results: 16 distinguished proteins were identified in DOPA-melanized yeast cells, as well as 15 triple-up-expressed proteins and 7 triple-downexpressed proteins in comparison with non DOPA-melanized yeast cells. Of note, proteins differentially expressed proteins were predominantly heat shock proteins. HSP90/60/70 genes expressions increased significantly demonstrated by q-RT-PCR, which was consistent with the proteomics changes. GO analysis showed that the majority of differentially expressed proteins including HSPs(especially HSP90) were found enriched in stress response, cellular process, protein folding, stimuli response and biological process. KEGG pathway analysis showed that proteins were enriched predominantly in phagosome. HSP90 inhibitor(Geldanamycin) inhibited the brown-black pigment production of T.marneffei yeast grown on brain heart infusion agar, as well as the inhibition effect was observed by transmission electron microscope. Conclusions: The results demonstrates that HSP90 palys an essential role in T.marneffei DOPA-melanin synthesis pathway.

Automated summary

The study identified the significant role of heat shock protein HSP90 in the melanin synthesis pathway of T.marneffei through proteomic analysis. The HSP90 inhibitor geldanamycin demonstrated effective inhibition of melanin production in T.marneffei yeast.