Ecto-enzymes of mammary gland and its tumors. Lectin inhibition of 5'-nucleotidase of the 13762 rat mammary ascites carcinoma.

Carraway, Kermit L.; Fogle, Dian; Chestnut, R.; Huggins, John W.; Carraway, Coralie A. Carothers

doi:10.1016/s0021-9258(20)81840-7

Cited by 58 publications

(17 citation statements)

References 31 publications

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“…If the envelopes are extracted with glycine-EDTAmercaptoethanol, a procedure which dissociates and solubilizes attached cytoskeletal elements containing actin, a-actinin, and actin binding protein (20,21), the inhibition becomes cooperative . Likewise, release of the enzyme from envelopes by detergent causes the inhibition reaction to become cooperative (7). These results provide circumstantial biochemical evidence for an effect of membrane-cytoskeleton interactions on the behavior of the ecto-enzyme.…”

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 66%

“…Con A specifically inhibits AMPase in intact cells (7,9,29), in isolated membranes (4,5,7,14,24,25), or in purified form (9,28). Since the reaction occurs at the cell surface, it can be studied without prior disruption of the cells (7,9,29). The enzyme reaction is simple ; kinetically, there appears to be a single enzyme form in the intact cells we have studied (7).…”

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 94%

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 98%

“…We have sought to eliminate some of these problems by studying a single concanavalin A (Con A) receptor, the enzyme 5'-nucleotidase (AMPase) . Con A specifically inhibits AMPase in intact cells (7,9,29), in isolated membranes (4,5,7,14,24,25), or in purified form (9,28). Since the reaction occurs at the cell surface, it can be studied without prior disruption of the cells (7,9,29).…”

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 99%

“…In previous studies, we have shown that the inhibition exhibits cooperativity (5) which is dependent on conditions that alter the "state" of the membrane in isolated membranes (7). In intact cells or cell surface envelopes isolated from Zn++stabilized cells the inhibition is noncooperative (7). If the envelopes are extracted with glycine-EDTAmercaptoethanol, a procedure which dissociates and solubilizes attached cytoskeletal elements containing actin, a-actinin, and actin binding protein (20,21), the inhibition becomes cooperative .…”

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 99%

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Effects of cytoskeletal perturbant drugs on ecto 5'-nucleotidase, a concanavalin A receptor.

Carraway¹,

Doss²,

Huggins³

et al. 1979

The Journal of Cell Biology

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The cooperativity of the inhibition of AMPase by Con A was investigated in MAT-A and MAT-Cl cells. Untreated cells exhibit no cooperativity . If either subline is treated with colchicine, cytochalasin B or D, or dibucaine, cooperativity is observed . Lumicolchicine has no effect . Theophylline or dibutyryl cyclic AMP prevents the effects of either colchicine or cytochalasin. The concentration required for half-maximal induction of cooperativity is 0.3-0.4 j,M for both colchicine and cytochalasin D, which is in the appropriate range for specific microtubule and microfilament disruptions . The effectiveness of the cytochalasins (E > D > B) is consistent with their known effects on microfilaments . No direct correlation was observed between the induction of cooperativity and drug-induced changes in Con A receptor redistributions or cell morphology . The morphology of MAT-A cells is grossly altered by cytochalasins or dibucaine and somewhat less by colchicine . MAT-C 1 cells exhibit more minor alterations in morphology as a result of these drug treatments . The results of this study indicate that the inhibition of AMPase, which is a Con A receptor, is a different process from the redistribution of the bulk of the Con A receptors, possibly reflecting short range membrane interactions rather than global effects on the cell . J . CELL BIOLOGY

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Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 66%

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 94%

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 98%

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 99%

Section: Abstract Cytoskeleton " 5'-nucleotidase Con a Receptors -Morphology -Cell Surfacementioning

confidence: 99%

See 3 more Smart Citations

Effects of cytoskeletal perturbant drugs on ecto 5'-nucleotidase, a concanavalin A receptor.

Carraway¹,

Doss²,

Huggins³

et al. 1979

The Journal of Cell Biology

Self Cite

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Effect of Lectins on the Activity of Brush Border Membrane‐Bound Enzymes of Rat Small Intestine

Erickson,

Kim,

Sleisenger

et al. 1985

J. pediatr. gastroenterol. nutr.

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Highly purified microvillus membrane vesicles isolated from rat small intestine were enriched in sucrase, maltase, and aminopeptidase activities. Approximately 90–95% of each enzyme was released from the membrane fraction by treatment with detergent (Triton X‐100) and sonication. Using untreated and solubilized preparations, the effect of lectin binding on the activity of each of the three enzymes was measured. It was observed that wheat germ agglutinin (WGA) and phytohemagglutinin (PHA) dramatically enhanced the activity of membrane‐bound maltase but had much less effect on the detergent solubilized enzyme. Under the same conditions aminopeptidase activity was inhibited by WGA and PHA while sucrase activity was not affected. These alterations in enzyme activity occurred at lectin concentrations that also precipitated each solubilized enzyme from solution. Inhibitory sugars prevented the alterations in enzyme activity suggesting that the effect is due to the binding of lectin to specific carbohydrate structures. Enhancement of membrane‐bound maltase activity by WGA and PHA was shown to be temperature dependent indicating that the lipid environment of the microvillus membrane may play a role in mediating the lectin effect. A kinetic analysis of the changes in maltase activity induced by these two lectins was due solely to an increase in Vmax. Two other lectins used in this study (concanavalin A and Ricinus communis agglutinin) did not readily precipitate the enzymes in question or alter their activity. These results show that binding of lectins to brush border membranes can induce variable changes in the activity of several membrane associated hydrolases, and suggest that similar changes may occur in vivo in the presence of dietary lectin. The consequences of such alterations on the ability of the intestinal mucosa to hydrolyze and absorb various dietary constituents is at present unknown.

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TGFβ regulation of membrane mucin Muc4 via proteosome degradation

Lomako

Soto

et al. 2009

J of Cellular Biochemistry

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Muc4 is a heterodimeric membrane mucin implicated in epithelial differentiation and tumor progression. It is expressed from a single gene as a 300 kDa precursor protein which is cleaved in the endoplasmic reticulum to its two subunits. Our previous work has shown that Muc4 is regulated by TGFβ, which represses the precursor cleavage. Working with Muc4-transfected A375 tumor cells, we now show that Muc4 undergoes proteosomal degradation. Proteosome inhibitors prolong the life of the precursor, shunt the Muc4 into cytoplasmic aggresomes, increase the level of Muc4 associated with the endoplasmic reticulum chaperones calnexin and calreticulin and increase the levels of ubiquitinated Muc4. Most importantly, proteosome inhibitors repress the TGFβ inhibition of Muc4 expression. These results suggest a model in which TGFβ inhibits precursor cleavage, shunting the precursor into the proteosomal degradation pathway. Thus, the cells have evolved a mechanism to use the quality control pathway for glycoproteins to control the quantity of the protein produced.

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Ecto-enzymes of mammary gland and its tumors. Lectin inhibition of 5'-nucleotidase of the 13762 rat mammary ascites carcinoma.

Cited by 58 publications

References 31 publications

Effects of cytoskeletal perturbant drugs on ecto 5'-nucleotidase, a concanavalin A receptor.

Effects of cytoskeletal perturbant drugs on ecto 5'-nucleotidase, a concanavalin A receptor.

Effect of Lectins on the Activity of Brush Border Membrane‐Bound Enzymes of Rat Small Intestine

TGFβ regulation of membrane mucin Muc4 via proteosome degradation

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