|Name:||solute carrier family 2 (facilitated glucose transporter), member 13|
|PubMed (11500374):|| Uldry M, Ibberson M, Horisberger JD, Chatton JY, Riederer BM, Thorens B. Identification of a mammalian H(+)-myo-inositol symporter expressedpredominantly in the brain.EMBO J. 2001 Aug 15;20(16):4467-77. PMID: 11500374 [PubMed - indexed for MEDLINE]|
Inositol and its phosphorylated derivatives play a major role in brain function, either as osmolytes, second messengers or regulators of vesicle endo- and exocytosis. Here we describe the identification and functional characterization of a novel H(+)-myo- inositol co-transporter, HMIT, expressed predominantly in the brain. HMIT cDNA encodes a 618 amino acid polypeptide with 12 predicted transmembrane domains. Functional expression of HMIT in Xenopus oocytes showed that transport activity was specific for myo-inositol and related stereoisomers with a Michaelis-Menten constant of approximately 100 microM, and that transport activity was strongly stimulated by decreasing pH. Electrophysiological measurements revealed that transport was electrogenic with a maximal transport activity reached at pH 5.0. In rat brain membrane preparations, HMIT appeared as a 75-90 kDa protein that could be converted to a 67 kDa band upon enzymatic deglycosylation. Immunofluorescence microscopy analysis showed HMIT expression in glial cells and some neurons. These data provide the first characterization of a mammalian H(+)-coupled myo- inositol transporter. Predominant central expression of HMIT suggests that it has a key role in the control of myo-inositol brain metabolism.
>sp|Q96QE2|MYCT_HUMAN Proton myo-inositol co-transporter (Hmit) - Homo sapiens (Human). MSRKASENVEYTLRSLSSLMGERRRKQPEPDAASAAGECSLLAAAESSTSLQSAGAGGGGVGDLERAARRQFQQDETPAF VYVVAVFSALGGFLFGYDTGVVSGAMLLLKRQLSLDALWQELLVSSTVGAAAVSALAGGALNGVFGRRAAILLASALFTA GSAVLAAANNKETLLAGRLVVGLGIGIASMTVPVYIAEVSPPNLRGRLVTINTLFITGGQFFASVVDGAFSYLQKDGWRY MLGLAAVPAVIQFFGFLFLPESPRWLIQKGQTQKARRILSQMRGNQTIDEEYDSIKNNIEEEEKEVGSAGPVICRMLSYP PTRRALIVGCGLQMFQQLSGINTIMYYSATILQMSGVEDDRLAIWLASVTAFTNFIFTLVGVWLVEKVGRRKLTFGSLAG TTVALIILALGFVLSAQVSPRITFKPIAPSGQNATCTRYSYCNECMLDPDCGFCYKMNKSTVIDSSCVPVNKASTNEAAW GRCENETKFKTEDIFWAYNFCPTPYSWTALLGLILYLVFFAPGMGPMPWTVNSEIYPLWARSTGNACSSGINWIFNVLVS LTFLHTAEYLTYYGAFFLYAGFAAVGLLFIYGCLPETKGKKLEEIESLFDNRLCTCGTSDSDEGRYIEYIRVKGSNYHLS DNDASDVE