Palmitoylation-Dependent Plasma Membrane Transport but Lipid Raft-Independent Signaling by Linker for Activation of T Cells

Hundt, Matthias; Harada, Yohsuke; Giorgio, Lauren De; Tanimura, Natsuko; Zhang, Weiguo; Altman, Amnon

doi:10.4049/jimmunol.0803921

Cited by 50 publications

(62 citation statements)

References 49 publications

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“…This relationship also extended to two palmitoylation site mutants (C26A and C29A; crosses in Fig. 4B), which previously have been shown to reduce raft-phase association and PM localization (30,36,37). Thus, perturbation of raft partitioning by three distinct means (TMD truncation, deletion of palmitoylation sites, and removal of physicochemical identity) had a common result: failure of the constructs to reach their proper destination in the PM.…”

Section: Significancesupporting

confidence: 53%

Membrane raft association is a determinant of plasma membrane localization

Diaz-Rohrer

Levental

Simons

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

193

215

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The lipid raft hypothesis proposes lateral domains driven by preferential interactions between sterols, sphingolipids, and specific proteins as a central mechanism for the regulation of membrane structure and function; however, experimental limitations in defining raft composition and properties have prevented unequivocal demonstration of their functional relevance. Here, we establish a quantitative, functional relationship between raft association and subcellular protein sorting. By systematic mutation of the transmembrane and juxtamembrane domains of a model transmembrane protein, linker for activation of T-cells (LAT), we generated a panel of variants possessing a range of raft affinities. These mutations revealed palmitoylation, transmembrane domain length, and transmembrane sequence to be critical determinants of membrane raft association. Moreover, plasma membrane (PM) localization was strictly dependent on raft partitioning across the entire panel of unrelated mutants, suggesting that raft association is necessary and sufficient for PM sorting of LAT. Abrogation of raft partitioning led to mistargeting to late endosomes/lysosomes because of a failure to recycle from early endosomes. These findings identify structural determinants of raft association and validate lipid-driven domain formation as a mechanism for endosomal protein sorting. membrane domain | endocytosis | trafficking | phase separation | microdomains R ecent advances in superresolution microscopy (1), lipid analysis (2, 3), and plasma membrane (PM) isolation (4, 5) have confirmed the coexistence of lipid-driven, fluid domains in biological membranes. The relatively ordered domains, known as "membrane rafts," have been proposed to be involved in protein sorting (6), viral/pathogen trafficking (3, 7), and PM signaling in a variety of contexts (8). However, despite the increasing evidence confirming the existence of dynamic, nanoscopic membrane rafts, the functional consequences of this phenomenon remain speculative because of the limitations of the previously used methods for defining raft association, i.e., the resistance of membrane components to solubilization by nonionic detergents (9).Lipid-mediated domains have been implicated as a mechanism for protein sorting in the latter stages of the secretory pathway (trans-Golgi network to the PM) (2, 6, 10-12), with analogous pathways mediating endosomal sorting/recycling (13,14). Raft lipids (i.e., sterols and sphingolipids) are significantly enriched at the PM (15-17), and recent observations confirm that these lipids also are enriched in sorting vesicles destined for the PM (2, 11). For proteins, several specific cytosolic signals exist for adapter/coat-mediated sorting between cellular organelles (18); in parallel, protein-lipid interactions through hydrophobic transmembrane domains (TMDs) also have been shown to regulate trafficking. For example, a strong correlation exists between the TMD length of bitopic proteins and their organelle specificity (19,20), with longer TMDs targeting proteins ...

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Section: Significancesupporting

confidence: 53%

Membrane raft association is a determinant of plasma membrane localization

Diaz-Rohrer

Levental

Simons

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

193

215

View full text Add to dashboard Cite

show abstract

“…However, more recent studies indicated that palmitoylation of LAT was required for the protein to be transported efficiently to the plasma membrane and that, in the absence of palmitoylation, LAT was susceptible to degradation (Gringhuis et al 2000;Hundt et al 2006;Tanimura et al 2006;Hundt et al 2009). Furthermore, LAT fusion proteins targeted to nonraft domains reconstituted LAT function in LAT-deficient Jurkat cells or LAT-deficient mice (Zhu et al 2005;Hundt et al 2009). These data raise the possibility that the signaling defects initially observed for a LAT palmitoylation mutant might result from defects in plasma membrane transport, rather than displacement from lipid domains.…”

Section: Palmitoylation and Membrane Localization Of Latmentioning

confidence: 99%

“…Hence it was proposed that lipid rafts provide a platform for assembly of signaling domains during T-cell activation. However, data from multiple studies indicated that membrane recruitment, not raft localization was required for LAT function (Zhu et al 2005;Hundt et al 2009). Furthermore, Harder and Kuhn showed that LAT, but not other raft-associated molecules such as Lck and GM1, was selectively enriched within plasma membrane fragments containing activated TCR, calling into question the view that upon TCR activation coalescence of raft-associated membrane proteins in the vicinity of activated TCR leads to T-cell triggering (Harderand Kuhn 2000).…”

Section: Mechanisms Of Assembly Of Lat Clusters and Lat-nucleated Commentioning

confidence: 99%

“…In the animal experiments, LAT knockout bone marrow cells were infected with retroviruses containing mutant LAT C26/29A. The infected bone marrow cells were transferred to irradiated wild type B6 mice and the mutant LAT was unable to mediate T-cell development (Hundt et al 2009). To assess whether raft localization (in addition to plasma membrane localization) was necessary for the in vivo function of LAT, several approaches have been taken using LAT fusion proteins.…”

Section: In Vivo Functions Of Lat Phosphotyrosines and Cysteinesmentioning

confidence: 99%

“…LAT-LAX and Src-LAT fusion proteins localized to the plasma membrane but not to rafts. Both of these fusion proteins mediated T-cell development in LAT-deficient environments (Zhu et al 2005;Hundt et al 2009). Therefore C26 and C29 of LATwere necessary for plasma membrane localization and for the in vivo function of LAT, but raft localization was not necessary for T-cell development.…”

Section: In Vivo Functions Of Lat Phosphotyrosines and Cysteinesmentioning

confidence: 99%

See 2 more Smart Citations

The LAT Story: A Tale of Cooperativity, Coordination, and Choreography

Balagopalan¹,

Coussens²,

Sherman³

et al. 2010

Cold Spring Harbor Perspectives in Biology

152

184

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The adapter molecule LAT is a nucleating site for multiprotein signaling complexes that are vital for the function and differentiation of T cells. Extensive investigation of LAT in multiple experimental systems has led to an integrated understanding of the formation, composition, regulation, dynamic movement, and function of LAT-nucleated signaling complexes. This review discusses interactions of signaling molecules that bind directly or indirectly to LAT and the role of cooperativity in stabilizing LAT-nucleated signaling complexes. In addition, it focuses on how imaging studies visualize signaling assemblies as signaling clusters and demonstrate their dynamic nature and cellular fate. Finally, this review explores the function of LAT based on the interpretation of mouse models using various LAT mutants.

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Identification of a New Cholesterol‐Binding Site within the IFN‐γ Receptor that is Required for Signal Transduction

et al. 2022

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The cytokine interferon-gamma (IFN-𝜸) is a master regulator of innate and adaptive immunity involved in a broad array of human diseases that range from atherosclerosis to cancer. IFN-𝜸 exerts it signaling action by binding to a specific cell surface receptor, the IFN-𝜸 receptor (IFN-𝜸R), whose activation critically depends on its partition into lipid nanodomains. However, little is known about the impact of specific lipids on IFN-𝜸R signal transduction activity. Here, a new conserved cholesterol (chol) binding motif localized within its single transmembrane domain is identified. Through direct binding, chol drives the partition of IFN-𝜸R2 chains into plasma membrane lipid nanodomains, orchestrating IFN-𝜸R oligomerization and transmembrane signaling. Bioinformatics studies show that the signature sequence stands for a conserved chol-binding motif presented in many mammalian membrane proteins. The discovery of chol as the molecular switch governing IFN-𝜸R transmembrane signaling represents a significant advance for understanding the mechanism of lipid selectivity by membrane proteins, but also for figuring out the role of lipids in modulating cell surface receptor function. Finally, this study suggests that inhibition of the chol-IFN𝜸R2 interaction may represent a potential therapeutic strategy for various IFN-𝜸-dependent diseases.

show abstract

Palmitoylation-Dependent Plasma Membrane Transport but Lipid Raft-Independent Signaling by Linker for Activation of T Cells

Cited by 50 publications

References 49 publications

Membrane raft association is a determinant of plasma membrane localization

Membrane raft association is a determinant of plasma membrane localization

The LAT Story: A Tale of Cooperativity, Coordination, and Choreography

Identification of a New Cholesterol‐Binding Site within the IFN‐γ Receptor that is Required for Signal Transduction

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