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Galectin-1 is implicated in the protein kinase C epsilon/vimentin-controlled trafficking of integrin-beta1 in glioblastoma cells.

Fortin S, Le Mercier M, Camby I, Spiegl-Kreinecker S, Berger W, Lefranc F, Kiss R - Brain Pathol. (2009)

Bottom Line: Galectin-1 depletion does not alter the gene expression level of integrin-beta1.Transient galectin-1 depletion effectuates as well the perinuclear accumulation of protein kinase C epsilon (PKCepsilon) and the intermediate filament vimentin, both of which have been shown to mediate integrin recycling in motile cells.Our results argue for the involvement of galectin-1 in the PKCepsilon/vimentin-controlled trafficking of integrin-beta1.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Toxicology, Institute of Pharmacy, Univesité Libre de Bruxelles, Brussels.

ABSTRACT
Cell motility and resistance to apoptosis characterize glioblastoma (GBM) growth and malignancy. In our current work we report that galectin-1, a homodimeric adhesion molecule and carbohydrate-binding protein with affinity for beta-galactosides, is linked with cell surface expression of integrin beta1 and the process of integrin trafficking. Using immunofluorescence, depletion of galectin-1 through both stable knockdown and transient-targeted small interfering RNA (siRNA) treatment induces an intracellular accumulation of integrin-beta1 coincident with a diminution of integrin-beta1 at points of cellular adhesion at the cell membrane. Galectin-1 depletion does not alter the gene expression level of integrin-beta1. Transient galectin-1 depletion effectuates as well the perinuclear accumulation of protein kinase C epsilon (PKCepsilon) and the intermediate filament vimentin, both of which have been shown to mediate integrin recycling in motile cells. Our results argue for the involvement of galectin-1 in the PKCepsilon/vimentin-controlled trafficking of integrin-beta1. The understanding of molecular mediators such as galectin-1 and the pathways through which they drive the cell invasion so descriptive of GBM is anticipated to reveal potential therapeutic targets that promote glioma malignancy.

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Related in: MedlinePlus

Integrin trafficking and endoplasmic reticulum (ER) to Golgi protein export pathways.A. Integrin trafficking depicting the two main pathways of internalization, clathrin-mediated and caveolar, as well as the pathways for recycling. Clathrin-mediated internalization utilizes clathrin coated pits, whereas caveolar internalization utilizes dynamin GTPase to form vesicles containing lipid rafts and caveolin protein. Recycling occurs through fusion to early endosomes and proceeds either via Rab4 signaling through a short loop pathway or via Rab11 signaling through a long loop pathway where proteins pass through the perinuclear recyling complex. Respective integrins and their trafficking mediators are listed above the suggested pathways that they utilize (9, 17, 19, 30, 31). B. ER to Golgi protein export depicting coat protein complex II (COPII)-mediated anterograde transport and coat protein complex I (COPI)-mediated retrograde transport between the ER and the Golgi complex. COPII assembly commences with Sar1 G-protein activation by the Sec12 guanine nucleotide exchange factor, followed by the recruitment of the Sec23–24 heterodimer that recognizes ER export signals on cargo proteins for inclusion in vesicles. The Sar1-Sec23–24 complex recruits the Sec13–31 heterodimer that facilitates final budding and vesicle formation from the ER. Vesicles proceed to the ER–Golgi intermediate compartment (ERGIC), which is also called vesicular tubular clusters (VTC), the complex of which transports proteins to the Golgi destination for eventual final export (15, 20, 23). GTP = guanosine-5′-triphosphate; SNARE = N-ethylmaleimide-sensitive fusion protein attachment protein receptor. PKC = protein kinase C.
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fig04: Integrin trafficking and endoplasmic reticulum (ER) to Golgi protein export pathways.A. Integrin trafficking depicting the two main pathways of internalization, clathrin-mediated and caveolar, as well as the pathways for recycling. Clathrin-mediated internalization utilizes clathrin coated pits, whereas caveolar internalization utilizes dynamin GTPase to form vesicles containing lipid rafts and caveolin protein. Recycling occurs through fusion to early endosomes and proceeds either via Rab4 signaling through a short loop pathway or via Rab11 signaling through a long loop pathway where proteins pass through the perinuclear recyling complex. Respective integrins and their trafficking mediators are listed above the suggested pathways that they utilize (9, 17, 19, 30, 31). B. ER to Golgi protein export depicting coat protein complex II (COPII)-mediated anterograde transport and coat protein complex I (COPI)-mediated retrograde transport between the ER and the Golgi complex. COPII assembly commences with Sar1 G-protein activation by the Sec12 guanine nucleotide exchange factor, followed by the recruitment of the Sec23–24 heterodimer that recognizes ER export signals on cargo proteins for inclusion in vesicles. The Sar1-Sec23–24 complex recruits the Sec13–31 heterodimer that facilitates final budding and vesicle formation from the ER. Vesicles proceed to the ER–Golgi intermediate compartment (ERGIC), which is also called vesicular tubular clusters (VTC), the complex of which transports proteins to the Golgi destination for eventual final export (15, 20, 23). GTP = guanosine-5′-triphosphate; SNARE = N-ethylmaleimide-sensitive fusion protein attachment protein receptor. PKC = protein kinase C.

Mentions: As treatment with galectin-1 siRNA causes a loss of membrane localized and an increase in intracellular localized integrin-β1 (Figure 3), we sought to determine if galectin-1 played a key role in directing either protein export pathways pertaining to integrins, or in integrin trafficking. We mapped out the processes of both integrin trafficking (Figure 4A) and of traditional protein export (Figure 4B), and compiled a list of the major genes directing these systems. Using the microarray analysis with the Affymetrix Human Genome U133 set Plus 2.0 on Hs683 cells left untreated, scramble-transfected, or transfected with siRNA targeting galectin-1, we inquired whether decreasing galectin-1 altered the gene expression of any of the genes on our list. We found a small set of genes whose expression was altered by at least 1.5-fold in either the control versus galectin-1 siRNA ratio or in the scramble siRNA versus galectin-1 siRNA ratio (Table 1). These data were merely to suggest whether integrin trafficking and/or protein export pathways may facilitate galectin-1-induced changes in integrin-β1 cellular localization, but did not solidify any particular genes as front-runners for potential mediators in these processes. These data show that galectin-1-targeted siRNA alters only to a small degree the gene expression of genes involved in integrin trafficking and protein export.


Galectin-1 is implicated in the protein kinase C epsilon/vimentin-controlled trafficking of integrin-beta1 in glioblastoma cells.

Fortin S, Le Mercier M, Camby I, Spiegl-Kreinecker S, Berger W, Lefranc F, Kiss R - Brain Pathol. (2009)

Integrin trafficking and endoplasmic reticulum (ER) to Golgi protein export pathways.A. Integrin trafficking depicting the two main pathways of internalization, clathrin-mediated and caveolar, as well as the pathways for recycling. Clathrin-mediated internalization utilizes clathrin coated pits, whereas caveolar internalization utilizes dynamin GTPase to form vesicles containing lipid rafts and caveolin protein. Recycling occurs through fusion to early endosomes and proceeds either via Rab4 signaling through a short loop pathway or via Rab11 signaling through a long loop pathway where proteins pass through the perinuclear recyling complex. Respective integrins and their trafficking mediators are listed above the suggested pathways that they utilize (9, 17, 19, 30, 31). B. ER to Golgi protein export depicting coat protein complex II (COPII)-mediated anterograde transport and coat protein complex I (COPI)-mediated retrograde transport between the ER and the Golgi complex. COPII assembly commences with Sar1 G-protein activation by the Sec12 guanine nucleotide exchange factor, followed by the recruitment of the Sec23–24 heterodimer that recognizes ER export signals on cargo proteins for inclusion in vesicles. The Sar1-Sec23–24 complex recruits the Sec13–31 heterodimer that facilitates final budding and vesicle formation from the ER. Vesicles proceed to the ER–Golgi intermediate compartment (ERGIC), which is also called vesicular tubular clusters (VTC), the complex of which transports proteins to the Golgi destination for eventual final export (15, 20, 23). GTP = guanosine-5′-triphosphate; SNARE = N-ethylmaleimide-sensitive fusion protein attachment protein receptor. PKC = protein kinase C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2805865&req=5

fig04: Integrin trafficking and endoplasmic reticulum (ER) to Golgi protein export pathways.A. Integrin trafficking depicting the two main pathways of internalization, clathrin-mediated and caveolar, as well as the pathways for recycling. Clathrin-mediated internalization utilizes clathrin coated pits, whereas caveolar internalization utilizes dynamin GTPase to form vesicles containing lipid rafts and caveolin protein. Recycling occurs through fusion to early endosomes and proceeds either via Rab4 signaling through a short loop pathway or via Rab11 signaling through a long loop pathway where proteins pass through the perinuclear recyling complex. Respective integrins and their trafficking mediators are listed above the suggested pathways that they utilize (9, 17, 19, 30, 31). B. ER to Golgi protein export depicting coat protein complex II (COPII)-mediated anterograde transport and coat protein complex I (COPI)-mediated retrograde transport between the ER and the Golgi complex. COPII assembly commences with Sar1 G-protein activation by the Sec12 guanine nucleotide exchange factor, followed by the recruitment of the Sec23–24 heterodimer that recognizes ER export signals on cargo proteins for inclusion in vesicles. The Sar1-Sec23–24 complex recruits the Sec13–31 heterodimer that facilitates final budding and vesicle formation from the ER. Vesicles proceed to the ER–Golgi intermediate compartment (ERGIC), which is also called vesicular tubular clusters (VTC), the complex of which transports proteins to the Golgi destination for eventual final export (15, 20, 23). GTP = guanosine-5′-triphosphate; SNARE = N-ethylmaleimide-sensitive fusion protein attachment protein receptor. PKC = protein kinase C.
Mentions: As treatment with galectin-1 siRNA causes a loss of membrane localized and an increase in intracellular localized integrin-β1 (Figure 3), we sought to determine if galectin-1 played a key role in directing either protein export pathways pertaining to integrins, or in integrin trafficking. We mapped out the processes of both integrin trafficking (Figure 4A) and of traditional protein export (Figure 4B), and compiled a list of the major genes directing these systems. Using the microarray analysis with the Affymetrix Human Genome U133 set Plus 2.0 on Hs683 cells left untreated, scramble-transfected, or transfected with siRNA targeting galectin-1, we inquired whether decreasing galectin-1 altered the gene expression of any of the genes on our list. We found a small set of genes whose expression was altered by at least 1.5-fold in either the control versus galectin-1 siRNA ratio or in the scramble siRNA versus galectin-1 siRNA ratio (Table 1). These data were merely to suggest whether integrin trafficking and/or protein export pathways may facilitate galectin-1-induced changes in integrin-β1 cellular localization, but did not solidify any particular genes as front-runners for potential mediators in these processes. These data show that galectin-1-targeted siRNA alters only to a small degree the gene expression of genes involved in integrin trafficking and protein export.

Bottom Line: Galectin-1 depletion does not alter the gene expression level of integrin-beta1.Transient galectin-1 depletion effectuates as well the perinuclear accumulation of protein kinase C epsilon (PKCepsilon) and the intermediate filament vimentin, both of which have been shown to mediate integrin recycling in motile cells.Our results argue for the involvement of galectin-1 in the PKCepsilon/vimentin-controlled trafficking of integrin-beta1.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Toxicology, Institute of Pharmacy, Univesité Libre de Bruxelles, Brussels.

ABSTRACT
Cell motility and resistance to apoptosis characterize glioblastoma (GBM) growth and malignancy. In our current work we report that galectin-1, a homodimeric adhesion molecule and carbohydrate-binding protein with affinity for beta-galactosides, is linked with cell surface expression of integrin beta1 and the process of integrin trafficking. Using immunofluorescence, depletion of galectin-1 through both stable knockdown and transient-targeted small interfering RNA (siRNA) treatment induces an intracellular accumulation of integrin-beta1 coincident with a diminution of integrin-beta1 at points of cellular adhesion at the cell membrane. Galectin-1 depletion does not alter the gene expression level of integrin-beta1. Transient galectin-1 depletion effectuates as well the perinuclear accumulation of protein kinase C epsilon (PKCepsilon) and the intermediate filament vimentin, both of which have been shown to mediate integrin recycling in motile cells. Our results argue for the involvement of galectin-1 in the PKCepsilon/vimentin-controlled trafficking of integrin-beta1. The understanding of molecular mediators such as galectin-1 and the pathways through which they drive the cell invasion so descriptive of GBM is anticipated to reveal potential therapeutic targets that promote glioma malignancy.

Show MeSH
Related in: MedlinePlus