Related Experiment Video

Updated: Aug 6, 2026

Spatial and Temporal Control of T Cell Activation Using a Photoactivatable Agonist
07:48

Spatial and Temporal Control of T Cell Activation Using a Photoactivatable Agonist

Published on: April 25, 2018

The TG2/LRP1 Pathway for T Cell Activation by Post-Translationally Modified Antigens

Agnele Sylvia Sewa1, Fu-Chen Yang2, Chaitan Khosla2,3,4

  • 1Department of Biochemistry, Stanford University School of Medicine, Stanford, California, USA.

Immunological Reviews
|August 5, 2026
PubMed

Post-translational modifications (PTMs) can generate neo-epitopes, modified peptides that evade immune tolerance and trigger immune responses. This review focuses on the TG2/LRP1 pathway as a new paradigm for coupling the formation of post-translationally modified peptides with their effective presentation as T-cell antigens by dendritic cells. Transglutaminase 2 (TG2) catalyzes the Gln → Glu conversion of specific residues in peptides derived from dietary gluten thereby enhancing their affinity for HLA-DQ2, the principal genetic determinant of celiac disease. However, because such modified peptides are scarce in intestinal mucosa, an effective mechanism for lysosomal uptake by antigen-presenting cells (APCs) is necessary. Protein-protein interaction between certain peptide-bound TG2 complexes and the low-density lipoprotein receptor-related protein 1 (LRP1) results in efficient endocytosis of these antigenic peptides along with their concomitant release in the endo-lysosomal compartment as deamidated products. An analogous PTM-driven mechanism for antigen presentation may also operate in autoimmune conditions associated with peptidylarginine deiminase (PADI) activity, such as rheumatoid arthritis (RA). The exquisite cellular selectivity of the TG2/LRP1 pathway has implications not only for understanding its role in autoimmunity but also for its potential exploitation in vaccine design.

Keywords:
TG2/LRP1 pathwayautoimmunityceliac diseasedendritic cellsneo‐epitopespost‐translational modification

More Related Videos

Retroviral Transduction of Bone Marrow Progenitor Cells to Generate T-cell Receptor Retrogenic Mice09:08

Retroviral Transduction of Bone Marrow Progenitor Cells to Generate T-cell Receptor Retrogenic Mice

Published on: July 11, 2016

Retroviral Transduction of T-cell Receptors in Mouse T-cells10:14

Retroviral Transduction of T-cell Receptors in Mouse T-cells

Published on: October 22, 2010

Related Concept Videos

TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
T Cell Activation and Clonal Selection01:22

T Cell Activation and Clonal Selection

T cells are integral to our adaptive immune system, recognizing and effectively responding to foreign antigens. T cell activation and clonal selection are pivotal in orchestrating this immune response. This article elucidates these mechanisms, detailing the roles of cluster of differentiation (CD) markers, major histocompatibility complex (MHC) molecules, costimulatory signals, and the process of clonal selection.
Naive T cells that have not yet encountered an antigen express two primary CD...
Receptor Tyrosine Kinases01:26

Receptor Tyrosine Kinases

Receptor tyrosine kinases or RTKs are membrane-bound receptors that phosphorylate specific tyrosine on protein substrates. RTKs regulate cellular growth, differentiation, survival, and migration. They contain an extracellular ligand binding domain, a transmembrane domain, and a cytosolic tail with intrinsic kinase activity. Several extracellular signaling molecules activate RTKs in one or more ways and relay the signal downstream. Ligands such as platelet-derived growth factor (PDGF) or...
Post-translational Translocation of Proteins to the RER01:27

Post-translational Translocation of Proteins to the RER

A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Amplifying Signals via Second Messengers01:15

Amplifying Signals via Second Messengers

Many receptor binding ligands are hydrophilic; they do not cross the cell membrane but bind to cell-surface receptors. Thus, their message must be relayed by second messengers present in the cell cytoplasm. There are several second messenger pathways, each with its own way of relaying information. For example, the G protein-coupled receptors can activate both phosphoinositol and cyclic AMP (cAMP) second messenger pathways. The phosphoinositol pathway is active when the receptor induces...
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...