title: 4F2hc stabilizes GLUT1 protein and increases glucose transport activity.
abstract: Glucose transporter 1 (GLUT1) is widely distributed throughout various tissues and contributes to insulin-independent basal glucose uptake. Using a split-ubiquitin membrane yeast two-hybrid system, we newly identified 4F2 heavy chain (4F2hc) as a membrane protein interacting with GLUT1. Though 4F2hc reportedly forms heterodimeric complexes between amino acid transporters, such as LAT1 and LAT2, and regulates amino acid uptake, we investigated the effects of 4F2hc on GLUT1 expression and the associated glucose uptake. First, FLAG-tagged 4F2hc and hemagglutinin-tagged GLUT1 were overexpressed in human embryonic kidney 293 cells and their association was confirmed by coimmunoprecipitation. The green fluorescent protein-tagged 4F2hc and DsRed-tagged GLUT1 showed significant, but incomplete, colocalization at the plasma membrane. In addition, an endogenous association between GLUT1 and 4F2hc was demonstrated using mouse brain tissue and HeLa cells. Interestingly, overexpression of 4F2hc increased the amount of GLUT1 protein in HeLa and HepG2 cells with increased glucose uptake. In contrast, small interfering RNA (siRNA)-mediated 4F2hc gene suppression markedly reduced GLUT1 protein in both cell types, with reduced glucose uptake. While GLUT1 mRNA levels were not affected by overexpression or gene silencing of 4F2hc, GLUT1 degradation after the addition of cycloheximide was significantly suppressed by 4F2hc overexpression and increased by 4F2hc siRNA treatment. Taken together, these observations indicate that 4F2hc is likely to be involved in GLUT1 stabilization and to contribute to the regulation of not only amino acid but also glucose metabolism.
authors.affiliation: Dept. of Medical Science, Graduate School of Medicine, University of Hiroshima, 1-2-3 Kasumi, Minami-ku, Hiroshima City, Hiroshima, Japan.
authors.forename: Haruya
authors.initials: H
authors.lastname: Ohno
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nakatsu
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sakoda
authors.forename: Akifumi
authors.initials: A
authors.lastname: Kushiyama
authors.forename: Hiraku
authors.initials: H
authors.lastname: Ono
authors.forename: Midori
authors.initials: M
authors.lastname: Fujishiro
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Otani
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Okubo
authors.forename: Masayasu
authors.initials: M
authors.lastname: Yoneda
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Fukushima
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kamata
authors.forename: Fusanori
authors.initials: F
authors.lastname: Nishimura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kurihara
authors.forename: Hideki
authors.initials: H
authors.lastname: Katagiri
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Oka
authors.forename: Tomoichiro
authors.initials: T
authors.lastname: Asano
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D003513:Cycloheximide / Q000494:pharmacology; D027282:Fusion Regulatory Protein 1, Heavy Chain / Q000378:metabolism*; D051272:Glucose Transporter Type 1 / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008297:Male; D051379:Mice; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D020798:Two-Hybrid System Techniques
chemical_list: D027282:Fusion Regulatory Protein 1, Heavy Chain; D051272:Glucose Transporter Type 1; D011500:Protein Synthesis Inhibitors; D034741:RNA, Small Interfering; C495677:SLC2A1 protein, human; C545989:SLC3A2 protein, human; C495678:Slc2a1 protein, mouse; C523212:Slc3A2 protein, mouse; D003513:Cycloheximide