Journal article
Compartmentalization of transport and phosphorylation of glucose in a hepatoma cell line
Biochemical journal, Vol.386(Pt 2), pp.245-253
03/01/2005
DOI: 10.1042/BJ20040901
PMCID: PMC1134788
PMID: 15473866
Abstract
The first steps of glucose metabolism are carried out by members of the families of GLUTs (glucose transporters) and HKs (hexokinases). Previous experiments using the inhibitor of glucose transport, CB (cytochalasin B), revealed that compartmentalization of GLUTs and HKs is a major factor in the control of glucose uptake in L6 myotubes [Whitesell, Ardehali, Printz, Beechem, Knobel, Piston, Granner, Van Der Meer, Perriott and May (2003) Biochem. J.
370
, 47–56]. In the present paper, we evaluate compartmentalization of GLUTs and HKs in a hepatoma cell line, H4IIE, which is characterized by excess GLUT activity, HKI in a particulate and a cytosolic fraction, and insignificant G6Pase (glucose-6-phosphatase) activity. The measured activity of glucose transport exceeded the rate of phosphorylation approx. 30-fold. Treatment with 25 μM CB (
K
i
∼3 μM in H4IIE cells) paradoxically increased the excess of GLUTs over phosphorylation (GLUTs are inhibited 80%, while phosphorylation is inhibited 98%). The global relationships of the data could be reconciled most simply by a two-compartment model. In this model, phosphorylation of glucose is carried out by a subset of HK molecules supplied by a subset of GLUTs that are more sensitive to CB than the other GLUTs. The agent, DCC (dicyclohexylcarbodi-imide) caused HKI to translocate from the particulate compartment to the cytosolic compartment and potently inhibited glucose phosphorylation. The particulate compartment may represent the mitochondria, to which the more CB-sensitive GLUTs may control the transport of glucose.
Details
- Title: Subtitle
- Compartmentalization of transport and phosphorylation of glucose in a hepatoma cell line
- Creators
- Richard R Whitesell - Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, U.S.AHossein Ardehali - Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, U.S.AJoseph M Beechem - †Molecular Probes, Inc., 29851 Willow Creek Road, Eugene, OR 97402, U.S.AAlvin C Powers - ‡VA Tennessee Valley Healthcare System, 1310 24th Avenue South, Nashville, TN 37212-2637, U.S.AWieb Van Der Meer - §Department of Physics and Astronomy, Western Kentucky University, 1 Big Red Way, Bowling Green, KY 42101, U.S.ALaureta M Perriott - ∥Department of Medicine (Diabetes, Endocrinology and Metabolism), Vanderbilt University School of Medicine, Nashville, TN 37232-6303, U.S.ADaryl K Granner - Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, U.S.A
- Resource Type
- Journal article
- Publication Details
- Biochemical journal, Vol.386(Pt 2), pp.245-253
- Publisher
- Portland Press Ltd
- DOI
- 10.1042/BJ20040901
- PMID
- 15473866
- PMCID
- PMC1134788
- ISSN
- 0264-6021
- eISSN
- 1470-8728
- Alternative title
- Compartmentalization of glucose transport and phosphorylation
- Language
- English
- Date published
- 03/01/2005
- Academic Unit
- Molecular Physiology and Biophysics
- Record Identifier
- 9984020639002771
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