N-glycosylation is crucial for trafficking and stability of SLC3A2 (CD98)

Console, Lara; Scalise, Mariafrancesca; Salerno, Simona; Scanga, Raffaella; Giudice, Deborah; Bartolo, Loredana De; Tonazzi, Annamaria; Indiveri, Cesare

doi:10.1038/s41598-022-18779-4

Cited by 17 publications

(14 citation statements)

References 41 publications

(58 reference statements)

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“…4F2hc harbors four N-glycosylation sites that are required for proper stability and trafficking to the membrane. Mutation of those sites correlates with a lower abundance of LAT1 in the plasma membrane and reduced transport activity [65]. We found in our cancer cell modes that when MYC was activated, the rhythmicity of 4F2hc glycosylation was lost, and increased expression of glycosylated 4F2hc was detected in all three cell lines.…”

Section: Discussionmentioning

confidence: 82%

“…We focused on the two subunits of the LAT1 amino acid transporter: LAT1 (SLC7A5) and 4F2hc (SLC3A2, also known as CD98), which transport glutamine and other amino acids, as well as the ubiquitously expressed GLUT1 glucose transporter (SLC2A1) [62][63][64]. GLUT1 and 4F2hc are glycosylated, which aids in their trafficking to the plasma membrane [65,66], so we performed immunoblot using a . CC-BY-NC-ND 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.…”

Section: Rhythmic Glycosylation and Expression Of Nutrient Transporte...mentioning

confidence: 99%

“…We focused on the two subunits of the LAT1 amino acid transporter: LAT1 (SLC7A5) and 4F2hc (SLC3A2, also known as CD98), which transport glutamine and other amino acids, as well as the ubiquitously expressed GLUT1 glucose transporter (SLC2A1) [62][63][64]. GLUT1 and 4F2hc are glycosylated, which aids in their trafficking to the plasma membrane [65,66], so we performed immunoblot using a technique to determine glycosylation level of these proteins [66]. Where appropriate, two different exposures of the same immunoblot ('dark' and 'light') are shown.…”

Section: Rhythmic Glycosylation and Expression Of Nutrient Transporte...mentioning

confidence: 99%

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MYC disrupts transcriptional and metabolic circadian oscillations in cancer and promotes enhanced biosynthesis

DeRollo

Cazarin

Shahidan

et al. 2023

Preprint

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The molecular circadian clock, which controls rhythmic 24-hour oscillation of genes, proteins, and metabolites, is disrupted across many human cancers. Deregulated expression of MYC oncoprotein has been shown to alter expression of molecular clock genes, leading to a disruption of molecular clock oscillation across cancer types. It remains unclear what benefit cancer cells gain from suppressing clock oscillation, and how this loss of molecular clock oscillation impacts global gene expression and metabolism in cancer. We hypothesized that MYC suppresses oscillation of gene expression and metabolism to instead upregulate pathways involved in biosynthesis in a static, non-oscillatory fashion. To test this, cells from distinct cancer types with inducible MYC or the closely related N-MYC were examined, using detailed time-series RNA-sequencing and metabolomics, to determine the extent to which MYC activation disrupts global oscillation of genes, gene expression, programs, and metabolites. We focused our analyses on genes, pathways, and metabolites that changed in common across multiple cancer cell line models. We report here that MYC disrupted over 85% of oscillating genes, while instead promoting enhanced ribosomal and mitochondrial biogenesis and suppressed cell attachment pathways. Notably, when MYC is activated, biosynthetic programs that were formerly circadian flipped to being upregulated in an oscillation-free manner. Further, activation of MYC ablates the oscillation of nutrient transporter glycosylation while greatly upregulating transporter expression, cell surface localization, and intracellular amino acid pools. Finally, we report that MYC disrupts metabolite oscillations and the temporal segregation of amino acid metabolism from nucleotide metabolism. Our results demonstrate that MYC disruption of the molecular circadian clock releases metabolic and biosynthetic processes from circadian control, which may provide a distinct advantage to cancer cells.

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Section: Discussionmentioning

confidence: 82%

Section: Rhythmic Glycosylation and Expression Of Nutrient Transporte...mentioning

confidence: 99%

“…We focused on the two subunits of the LAT1 amino acid transporter: LAT1 (SLC7A5) and 4F2hc (SLC3A2, also known as CD98), which transport glutamine and other amino acids, as well as the ubiquitously expressed GLUT1 glucose transporter (SLC2A1) [62][63][64]. GLUT1 and 4F2hc are glycosylated, which aids in their trafficking to the plasma membrane [65,66], so we performed immunoblot using a technique to determine glycosylation level of these proteins [66]. Where appropriate, two different exposures of the same immunoblot ('dark' and 'light') are shown.…”

Section: Rhythmic Glycosylation and Expression Of Nutrient Transporte...mentioning

confidence: 99%

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MYC disrupts transcriptional and metabolic circadian oscillations in cancer and promotes enhanced biosynthesis

DeRollo

Cazarin

Shahidan

et al. 2023

Preprint

View full text Add to dashboard Cite

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“…Beyond its function, SLC7A5 acts through heterodimerizing with SLC3A2 (CD98 heavy chain; CD98hc). This is interesting regarding our study since CD98hc is a N-glycosylated protein [ 45 ] and SLC7A5 (LAT1) is one of its associated light chain ensuring amino acids transport. These data suggest that membrane-embedded IgG2B could substitute SLC3A2 to form a membrane heterodimer with SLC7A5.…”

Section: Resultsmentioning

confidence: 99%

Astrocytes express aberrant immunoglobulins as putative gatekeeper of astrocytes to neuronal progenitor conversion

et al. 2023

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Using multi-omics analyses including RNAseq, RT-PCR, RACE-PCR, and shotgun proteomic with enrichment strategies, we demonstrated that newborn rat astrocytes produce neural immunoglobulin constant and variable heavy chains as well as light chains. However, their edification is different from the ones found in B cells and they resemble aberrant immunoglobulins observed in several cancers. Moreover, the complete enzymatic V(D)J recombination complex has also been identified in astrocytes. In addition, the constant heavy chain is also present in adult rat astrocytes, whereas in primary astrocytes from human fetus we identified constant and variable kappa chains as well as the substitution lambda chains known to be involved in pre-B cells. To gather insights into the function of these neural IgGs, CRISPR-Cas9 of IgG2B constant heavy chain encoding gene (Igh6), IgG2B overexpression, proximal labeling of rat astrocytes IgG2B and targets identification through 2D gels were performed. In Igh6 KO astrocytes, overrepresentation of factors involved in hematopoietic cells, neural stem cells, and the regulation of neuritogenesis have been identified. Moreover, overexpression of IgG2B in astrocytes induces the CRTC1-CREB-BDNF signaling pathway known to be involved in gliogenesis, whereas Igh6 KO triggers the BMP/YAP1/TEAD3 pathway activated in astrocytes dedifferentiation into neural progenitors. Proximal labeling experiments revealed that IgG2B is N-glycosylated by the OST complex, addressed to vesicle membranes containing the ATPase complex, and behaves partially like CD98hc through its association with LAT1. These experiments also suggest that proximal IgG2B-LAT1 interaction occurs concomitantly with MACO-1 and C2CD2L, at the heart of a potentially novel cell signaling platform. Finally, we demonstrated that these chains are synthesized individually and associated to recognize specific targets. Indeed, intermediate filaments Eif4a2 and Pdia6 involved in astrocyte fate constitute targets for these neural IgGs. Taken together, we hypothese that neural aberrant IgG chains may act as gatekeepers of astrocytes' fate.

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“…This heterodimer is characterized by a covalent bond between two conserved cysteines, C164 of the light subunit LAT1 and C109 of the heavy subunit CD98 [ 1 , 2 , 3 , 4 , 5 ]. CD98 is involved in the membrane trafficking [ 6 , 7 ] of LAT1, which is the sole subunit responsible for the transport function. It catalyzes an electroneutral antiport of amino acids with specificity for essential amino acids [ 1 , 2 , 3 , 4 , 5 ] and cysteine [ 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Insights into the Transport Cycle of LAT1 and Interaction with the Inhibitor JPH203

Brunocilla

Console

Rovella

et al. 2023

IJMS

Self Cite

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The large Amino Acid Transporter 1 (LAT1) is an interesting target in drug discovery since this transporter is overexpressed in several human cancers. Furthermore, due to its location in the blood-brain barrier (BBB), LAT1 is interesting for delivering pro-drugs to the brain. In this work, we focused on defining the transport cycle of LAT1 using an in silico approach. So far, studies of the interaction of LAT1 with substrates and inhibitors have not considered that the transporter must undergo at least four different conformations to complete the transport cycle. We built outward-open and inward-occluded conformations of LAT1 using an optimized homology modelling procedure. We used these 3D models and the cryo-EM structures in outward-occluded and inward-open conformations to define the substrate/protein interaction during the transport cycle. We found that the binding scores for the substrate depend on the conformation, with the occluded states as the crucial steps affecting the substrate affinity. Finally, we analyzed the interaction of JPH203, a high-affinity inhibitor of LAT1. The results indicate that conformational states must be considered for in silico analyses and early-stage drug discovery. The two built models, together with the available cryo-EM 3D structures, provide important information on the LAT1 transport cycle, which could be used to speed up the identification of potential inhibitors through in silico screening.

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N-glycosylation is crucial for trafficking and stability of SLC3A2 (CD98)

Cited by 17 publications

References 41 publications

MYC disrupts transcriptional and metabolic circadian oscillations in cancer and promotes enhanced biosynthesis

MYC disrupts transcriptional and metabolic circadian oscillations in cancer and promotes enhanced biosynthesis

Astrocytes express aberrant immunoglobulins as putative gatekeeper of astrocytes to neuronal progenitor conversion

Insights into the Transport Cycle of LAT1 and Interaction with the Inhibitor JPH203

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