Involvement of sulfhydryl groups in the action of insulin and radiation on thymocyte Na+-dependent amino acid transport

Kwock, Lester; Hefter, K.

doi:10.1016/0005-2736(76)90374-6

Cited by 36 publications

(10 citation statements)

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“…Hare (4) observed that PCMB-S inhibits System L amino acid transport to a greater extent than System A in mouse embryo cells. His observations, together with those of Kwock and his colleagues (5,6) on the effects of y-ray irradiation on amino acid transport in thymocytes suggest that System L transport components, like those mediating glucose transport, have sulfhydryl groups lying near the exofacial membrane surface whereas the sulfhydryl reactant-sensitive sites of System A transport components lie near the endofacial surface or in hydrophobic regions of the membrane (7).…”

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confidence: 99%

Involvement of membrane sulfhydryls in the activation and maintenance of nutrient transport in chick embryo fibroblasts

et al. 1977

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At 5 microgram/ml, insulin stimulates hexose, A-system amino acid, and nucleoside transport by serum-starved chick embryo fibroblasts (CEF). This stimulation, although variable, is comparable to that induced by 4% serum. The sulfhydryl oxidants diamide (1-20 micrometer). hydrogen peroxide (500 micrometer), and methylene blue (50 micrometer) mimic the effect of insulin in CEF. PCMB-S,1 a sulfhydryl-reacting compound which penetrates the membrane slowly, has a complex effect on nutrient transport in serum- and glucose-starved CEF. Hexose uptake is inhibited by 0.1-1 mM PCMB-S in a time- and concentration-dependent manner, whereas A-system amino acid transport is inhibited maximally within 10 min of incubation and approaches control rates after 60 min. A differential sensitivity of CEF transport systems is also seen in cells exposed to membrane-impermeant glutathione-maleimide I, designated GS-Mal. At 2 mM GS-Mal reduces the rate of hexose uptake 80-100% in serum- and glucose-starved CEF; in contrast A-system amino acid uptake is unaffected. D-glucose, but not -L-glucose or cytochalasin B, protects against GS-Mal inhibition. These results are consistent with the hypothesis that sulfhydryl groups are involved in nutrient transport and that those sulfhydryls associated with the hexose transport system and essential for its function are located near the exofacial surface of the membrane in CEF.

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Involvement of membrane sulfhydryls in the activation and maintenance of nutrient transport in chick embryo fibroblasts

et al. 1977

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“…Similarly, treatment of these cells with insulin, which we and others have suggested modulates transport activity by inducing disulfide formation in membranes, increases AIB uptake in these vesicles (Kwock et al, 1976;Czech et al, 1974). involved in modulating Na+-dependent amino acid transport in thymocytes and are consistent with our hypothesis concerning the role of -SH groups in the uptake of Na+-dependent amino acids in these cells (Kwock et al, 1976;. However, this modulation by membrane -SH groups of Na+-dependent neutral amino acid transport systems may not be limited to lymphoid cells.…”

Section: As Shown Inmentioning

confidence: 85%

“…We have suggested that AIB transport in thymocytes is stimulated when a putative plasma membrane component is in a disulfide form and decreased when it is in its reduced form (Kwock et al, 1976 By sulfhydryl-disulfide interchange processes (White et al, 1964) reduced glutathione (GSH) can reduce nonenzymatically disulfide linkages whereas oxidized glutathione (GSSG) can convert free adjacent sulfhydryl groups to their corresponding disulfides. Thus, if our hypothesis is correct, GSH treatment should lead to inhibition of uptake whereas GSSG should increase uptake of AIB.…”

Section: As Shown Inmentioning

confidence: 98%

“…Sulfhydryl groups are important to membrane function but the mechanisms by which changes in these groups affect membrane processes are not well understood. In lymphoid cells, we have shown that sulfhydryl groups appear to be able to modulate plasma membrane Na+-dependent amino acid transport (Kwock et al, 1976(Kwock et al, , 1979. This transport system is intimately involved in cellular growth and differentiation processes (Oxender et al, 1977;Guidotti et al, 1978).…”

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confidence: 99%

“…This transport system is intimately involved in cellular growth and differentiation processes (Oxender et al, 1977;Guidotti et al, 1978). We have proposed that transport of Na+-dependent amino acids is dependent upon the steady state of critical plasma membrane sulfhydryl groups (Kwock et al, 1976). When these sulfhydryl groups are in the disulfide form (i.e., -S-S-) the potential energy barrier for the movement of the amino acid carrier protein is reduced, whereas when they are in the reduced sulfhydryl group form (i.e., -SH), the potential energy barrier for transport is increased.…”

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confidence: 99%

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Sulfhydyl group involvement in the modulation of neutral amino acid transport in thymocyte membrane vesicles

Kwock

1981

Journal Cellular Physiology

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Membrane vesicles from rat thymocytes accumulate 2-aminoisobutyric acid in the presence of 0. 1 M NaCl. Uptake is half maximal between 15 and 30 seconds after addition of the amino acid and reaches a plateau value after about 2 minutes. The uptake of 2-aminoisobutyric acid can be modulated by various sulfhydryl reagents. Reduced glutathione leads to an inhibition of uptake whereas oxidized glutathione increases uptake. Agents such as insulin and diamide which can induce disulfide formation lead to an activation of transport. These date indicate that uptake of the Na+-dependent amino acid, 2-aminoisobutyric acid, in thymocytes is modulated by a putative plasma membrane, sulfhydryl-containing protein.

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Characterization of a polyamine transport system in murine embryonic palate mesenchymal cells

Gawel-Thompson

Greene

1988

Journal Cellular Physiology

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Polyamines (putrescine, spermidine, and spermine) are normal cellular constituents able to modulate cellular proliferation and differentiation in a number of developing systems. Ornithine decarboxylase (ODC), the rate-limiting enzyme in the polyamine biosynthetic pathway, has been shown to be causally related to an increase in glycosaminoglycan synthesis in murine embryonic palatal mesenchyme cells (MEPM). In order to understand other mechanisms that exist to regulate polyamine levels in cells derived from the developing craniofacial area, the present study investigated the capacity of MEPM cells to accumulate exogenous putrescine and tests the hypothesis that polyamine transport can serve as an adaptational response of MEPM cells to a change in their ability to synthesize polyamines. Transport was initiated in confluent cultures of MEPM cells by the addition of 0.1 microCi/ml of 14C-putrescine. The rate of transport, monitored for 20-120 minutes, was found to be a time-dependent saturable process. The rate of initial transport, determined by incubating MEPM cells for 15 minutes in the presence of different concentrations (1.0-20.0 microM) of 14C-putrescine, was also found to be saturable, suggesting a carrier-mediated event. Lineweaver-Burk analysis of these data revealed an apparent Km of 5.78 microM and a Vmax of 2.63 nmol/mg protein/15 minutes. Transport measured either at 4 degrees C or in the presence of 2-4 DNP was dramatically inhibited. Thus, putrescine transport is an active process, dependent upon metabolic energy. Conditions in which 1) NaCl was iso-osmotically replaced with choline chloride or 2) the Na+-electrochemical gradient was dissipated with Na+, K+-specific ionophores resulted in a decreased rate of transport indicating that putrescine transport in these cells is Na+ dependent. Noncompetitive inhibition assays utilizing sulfhydryl reagents that blocked sulfhydryl groups inhibited putrescine transport, suggesting that sulfhydryl groups are important for putrescine uptake. Competitive inhibition assays demonstrated that while spermidine and spermine inhibited putrescine uptake, ornithine did not inhibit transport. Spermidine, spermine, and putrescine thus appear to share a common transport system that is separate from that for ornithine. Putrescine transport is subject to adaptive regulation in both exponentially growing and confluent cultures of MEPM cells.(ABSTRACT TRUNCATED AT 400 WORDS)

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Involvement of sulfhydryl groups in the action of insulin and radiation on thymocyte Na+-dependent amino acid transport

Cited by 36 publications

References 11 publications

Involvement of membrane sulfhydryls in the activation and maintenance of nutrient transport in chick embryo fibroblasts

Involvement of membrane sulfhydryls in the activation and maintenance of nutrient transport in chick embryo fibroblasts

Sulfhydyl group involvement in the modulation of neutral amino acid transport in thymocyte membrane vesicles

Characterization of a polyamine transport system in murine embryonic palate mesenchymal cells

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