Prohibitin (PHB, also known as PHB1 or BAP32), is a highly conserved 31kDa protein that expressed in many cellular compartments, such as mitochondria, nucleus, cytosol, and plasma membrane, and plays roles in regulating the transcription of genes, apoptosis, and mitochondrial biogenesis. There is a report that Prohibitin expression is required for the stimulation of pigmentation by melanogenin. However, no studies have been published on the function of PHB in melanocytes, especially in melanosome transport. : Immunofluorescence was performed to confirm the localization of PHB. RNA transfections, Co-immunoprecipitation, western blotting and proximity ligation assay were performed to find binding state between proteins and demonstrate functions of PHB on melanosome transport. : PHB is located in the melanosome and perinuclear aggregation of melanosome is induced when expression of PHB is reduced with no influence on melanin contents. PHB binds directly to Rab27a and Mlph but not Myosin-Va. Rab27a and Mlph bind to specific domains of PHB. Reduced expression of PHB led to the impaired binding affinity between Rab27a and Mlph. : PHB regulates melanosome transport by linking to Rab27a and Mlph in melanocytes. Targeting and regulating PHB not only manages pigmentation in melanocytes, but also controls hyperpigmentation in melanoma.
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http://dx.doi.org/10.7150/thno.41383 | DOI Listing |
J Cell Sci
January 2025
Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
Various N-terminal tags have often been used to identify the functions and localization of Rab small GTPases, but their impact on Rab proteins themselves has been poorly investigated. Here, we used a knockout (KO)-rescue approach to systematically evaluate the effect of N-terminal tagging of two Rabs, Rab10 and Rab27A, on Rab10-KO HeLa cells and Rab27A-deficient melanocytes (melan-ash cells), respectively. The results showed that all of the N-terminal-tagged Rab27A proteins mediated actin-based melanosome transport in the melan-ash cells, but none of the N-terminal-tagged Rab10 proteins fully rescued the defect in tubular endosome formation in the Rab10-KO cells.
View Article and Find Full Text PDFWhile it has been appreciated for decades that lysosomes can import cysteine, its for organismal physiology is unclear. Recently, the MFSD12 transmembrane protein was shown to be necessary to import cysteine into lysosomes (and melanosomes), enabling the study of these processes using genetic tools. Here, we find that mice lacking die between embryonic days 10.
View Article and Find Full Text PDFCureus
December 2024
Department of Pathology, Ranga Raya Medical College, Kakinada, IND.
Chediak-Higashi syndrome (CHS) is a rare multisystem genetic disorder of childhood, caused by a defect in vesicular trafficking, which is an essential process for intracellular transport. This defect results in the formation of giant cytoplasmic granules in various cell types, including white blood cells, melanosomes, and Schwann cells. The presence of giant lysosomal granules in neutrophils and their precursors is a distinct and diagnostic feature of CHS, differentiating it from other childhood immunodeficiency disorders, such as Griscelli syndrome and Hermansky-Pudlak syndrome, which share common characteristics like albinism and increased susceptibility to fatal hemophagocytic lymphohistiocytosis.
View Article and Find Full Text PDFBiomol Biomed
December 2024
Department and Institute of Infectious Disease, Tongji Hospital, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China.
Chronic liver disease (CLD) is a significant global health concern that leads to increased morbidity and mortality, and is associated with skin pigmentation changes. Excessive facial pigmentation is a common characteristic of patients with CLD, although the exact mechanism underlying this phenomenon remains unclear. Melanin, which consists of eumelanin and pheomelanin, is synthesized in melanocytes.
View Article and Find Full Text PDFJ Biosci Bioeng
December 2024
Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501, Japan; Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan. Electronic address:
Hair color is formed through a series of processes such as melanin synthesis and storage in melanosomes, transfer from melanocytes, and reception by hair matrix cells in the hair bulb. Because gray hair is caused by the deterioration of a single or multiple of these processes, understanding the mechanisms responsible for these processes is crucial for developing therapeutic strategies. Recently, a robust approach for preparing hair follicle organoids (HFOs) was reported, in which hair follicle morphogenesis, including hair shaft elongation, was tracked in vitro.
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