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Physiology and cell biology of clinical mutants of the human riboflavin transporter‐2: studies utilizing the human‐derived brain U87 cells (896.2)
Author(s) -
Subramanian Veedamali,
Kapadia Rubina,
Ghosal Abhisek,
Said Hamid
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.896.2
Subject(s) - mutant , microbiology and biotechnology , cell , endoplasmic reticulum , biology , transporter , cell physiology , cell culture , chemistry , biochemistry , gene , genetics
Riboflavin (RF) is essential for normal cellular functions of all cells including those of the brain. RF is transported into human cells via three membrane transporters, hRFVT‐1,‐2 and ‐3. Mutation in hRFVT‐2 (which is predominantly expressed in brain cells) is believed to be the cause of the rare neurodegenerative disorder, Brown‐Vialetto‐Van Laere Syndrome (BVVLS). Little,however, is known about how such mutations affect the physiology and cell biology of hRFVT‐2. We addressed this issue using the human‐derived brain U87cells as model and live cell confocal imaging. Our results showed marked inhibition in RF uptake in U87 cells stably expressing clinical mutants L123P, L140P, G306R and L339P. Live cell confocal imaging of U87 cells stably expressing hRFVT‐2 clinical mutants showed the L123P and L339P mutants were retained within the endoplasmic reticulum, while the L140P and G306R mutants were expressed at the cell membrane though at reduced protein expression levels compared to wild‐type construct. These results show that some of the BVVLS associated mutations in hRFVT‐2 affect the transporter functionality and that this effect is mediated via alterations in membrane targeting and/or protein expression. (Supported by DVA and NIH grant DK 56061‐15). Grant Funding Source : DVA and NIH