PMID- 10318794
OWN - NLM
STAT- MEDLINE
DCOM- 19990617
LR  - 20210209
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 274
IP  - 20
DP  - 1999 May 14
TI  - Transmembrane topology of human glucose 6-phosphate transporter.
PG  - 13865-9
AB  - Glycogen storage disease type 1b is caused by a deficiency in a glucose
      6-phosphate transporter (G6PT) that translocates glucose 6-phosphate from the
      cytoplasm to the endoplasmic reticulum lumen where the active site of glucose
      6-phosphatase is situated. Using amino- and carboxyl-terminal tagged G6PT, we
      demonstrate that proteolytic digestion of intact microsomes resulted in the
      cleavage of both tags, indicating that both termini of G6PT face the cytoplasm.
      This is consistent with ten and twelve transmembrane domain models for G6PT
      predicted by hydropathy analyses. A region of G6PT corresponding to amino acid
      residues 50-71, which constitute a transmembrane segment in the twelve-domain
      model, are situated in a 51-residue luminal loop in the ten-domain model. To
      determine which of these two models is correct, we generated two G6PT mutants,
      T53N and S55N, that created a potential Asn-linked glycosylation site at residues
      53-55 (N53SS) or 55-57 (N55QS), respectively. N53SS or N55QS would be
      glycosylated only if it is situated in a luminal loop larger than 33 residues as 
      predicted by the ten-domain model. Whereas wild-type G6PT is not a glycoprotein, 
      both T53N and S55N mutants are glycosylated, strongly supporting the ten-helical 
      model for G6PT.
FAU - Pan, C J
AU  - Pan CJ
AD  - Heritable Disorders Branch, NICHHD, National Institutes of Health, Bethesda,
      Maryland 20892, USA.
FAU - Lin, B
AU  - Lin B
FAU - Chou, J Y
AU  - Chou JY
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Antiporters)
RN  - 0 (Antiviral Agents)
RN  - 0 (Monosaccharide Transport Proteins)
RN  - 0 (SLC37A4 protein, human)
RN  - 0 (Slc37a4 protein, mouse)
RN  - 0 (Slc37a4 protein, rat)
RN  - 0 (glucose 6-phosphate(transporter))
RN  - 11089-65-9 (Tunicamycin)
SB  - IM
MH  - Amino Acid Sequence
MH  - Animals
MH  - Antiporters/*chemistry
MH  - Antiviral Agents/pharmacology
MH  - Blotting, Western
MH  - Cell Membrane/*chemistry
MH  - Humans
MH  - Mice
MH  - Molecular Sequence Data
MH  - Monosaccharide Transport Proteins/*chemistry
MH  - Protein Structure, Secondary
MH  - Rats
MH  - Tunicamycin/pharmacology
EDAT- 1999/05/13 00:00
MHDA- 1999/05/13 00:01
CRDT- 1999/05/13 00:00
PHST- 1999/05/13 00:00 [pubmed]
PHST- 1999/05/13 00:01 [medline]
PHST- 1999/05/13 00:00 [entrez]
AID - 10.1074/jbc.274.20.13865 [doi]
AID - S0021-9258(19)73246-3 [pii]
PST - ppublish
SO  - J Biol Chem. 1999 May 14;274(20):13865-9. doi: 10.1074/jbc.274.20.13865.