ReferenceID 2768

Rhamnazin suppresses melanosome transport by promoting the ubiquitin-mediated proteasomal degradation of melanophilin

J Dermatol Sci

Background: Melanosomes are intracellularly transported from the perinuclear region to the cell periphery and then to neighboring keratinocytes. We recently reported that the flavonoid rhamnazin suppresses melanosomal tr

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Reference Id
2768
Evidence Id
19358
Core Evidence Id
19358
Source Reference Id
5535
Herb2 Reference Id
HBREF006332
Subject Paper Key
HBIN042151_34955374
Pubmed Id
34955374
Doi
10.1016/j.jdermsci.2021.12.003
Paper Title
Rhamnazin suppresses melanosome transport by promoting the ubiquitin-mediated proteasomal degradation of melanophilin
Paper Abstract
Background: Melanosomes are intracellularly transported from the perinuclear region to the cell periphery and then to neighboring keratinocytes. We recently reported that the flavonoid rhamnazin suppresses melanosomal transport within pigment cells, yet the action mechanism remained unclear. Objective: Our aim was to elucidate how rhamnazin influences the intracellular transport of melanosomes. Methods: A melanosome distribution assay and immunostaining were performed using B16F10 mouse melanoma cells and normal human epidermal melanocytes, respectively. Expression levels of melanosome transport-related proteins, including melanophilin (MLPH), RAB27A, and myosin VA (MYO5A), were analyzed by immunoblotting. Ubiquitinated MLPH was detected using a commercial ubiquitin detection kit. To investigate the interaction between rhamnazin and MLPH, we prepared rhamnazin conjugated with magnetic FG beads. Results: Immunoblotting analysis revealed that rhamnazin specifically reduces the expression of MLPH but not RAB27A or MYO5A proteins. The ubiquitin detection assay, which made use of a proteasome inhibitor, showed that MLPH accumulated as a polyubiquitinated protein after treatment with rhamnazin. We speculated that the affinity of rhamnazin for the components of the melanosome transport-related tripartite complex may alter the stability of the formation of the tripartite assembly. By using affinity-based techniques with B16F10 whole cell lysates or recombinant MLPH and RAB27A proteins, we revealed the interaction of rhamnazin with the components of the tripartite complex. Conclusion: We found that rhamnazin inhibits intracellular transport of melanosomes through proteasomal degradation of MLPH. Our results suggest that topical application of rhamnazin may provide a new approach for treating skin pigmentation disorders.
Journal
J Dermatol Sci
Publish Year
2021
Experiment Subject
mouse; human; b16f10 mouse melanoma cells
Experiment Type
Cell Experiment
Phenotype Related
Melanoma; Skin Pigmentation Disorders
Paper Title Cn
Paper Title En
Rhamnazin suppresses melanosome transport by promoting the ubiquitin-mediated proteasomal degradation of melanophilin
Bilingual Status
semi_complete