40 Questions
What is the role of CD4 or CD8 co-receptor in the T cell intracellular signaling pathway?
Enhances the stability of TCR-MHC-peptide interaction
What initiates the formation of an increasingly stable immune synapse in the T cell signaling pathway?
TCR binding to MHC-peptide complex
Which proteins act as recruitment sites for other signaling proteins once phosphorylated in the T cell intracellular signaling pathway?
P-Tyr residues on CD3 & zeta chains
What is the main function of the immune synapse in coordinating immune responses?
Ensuring specific target cell killing by CTLs
Which event occurs first in the T cell intracellular signal pathway?
TCR binding specific peptide-MHC complex
Which components make up the TCR complex?
TCR, two CD3 heterodimers, zeta homodimer
What is the composition of the TCR itself?
Alpha and beta chains
Which part of the TCR complex serves as a sensor for the T cell?
TCR
Which region of the TCR is the most variable and critical for antigen recognition?
Hypervariable Complementarity-Determining Region (CDR) loops
What initiates signaling in the TCR complex upon binding to MHC presenting an antigen peptide?
Binding of TCR to the antigen peptide
Which part of the TCR complex contains ITAMs in their cytoplasmic tails?
CD3 and zeta chains
What type of bonds contribute to the stability and proper folding of the TCR chains?
Disulfide Bonds
Which domain is characteristic of proteins in the immunoglobulin superfamily and is involved in antigen recognition?
Immunoglobulin (Ig) Domain
Which structure enables T cells to recognize a wide range of antigens and initiate immune responses?
Hypervariable Complementarity-Determining Region (CDR) loops
What is the primary function of the TCR complex in signal transduction?
Transduce signal from MHC/antigen binding to T cell activation
Which protein is primarily expressed on CD4+ T cells and serves as a co-receptor for helper T lymphocytes?
CD4
What is the main role of CD8 as a co-receptor in T cells?
Stabilizing the TCR-MHC-peptide complex interaction
Which type of cells primarily express CD8 as a co-receptor?
Cytotoxic T cells
What is the function of CD4 in the context of T cell activation?
Stabilizing the interaction of TCR with MHC-peptide complex
When a CD4+ T cell encounters an antigen-presenting cell displaying a peptide bound to class II MHC molecules, what does the CD4 co-receptor bind to?
Region of the MHC molecule outside the peptide-binding groove
What is the role of CD8 co-receptor in T cell activation?
Stabilizes the interaction between TCR and MHC-peptide complex
Which molecules do CD8 co-receptors bind to during T cell activation?
Class I MHC molecules
What is the key defining feature of CD4+ helper T cells?
Express CD4 co-receptors on their surface
How do CD4 and CD8 co-receptors contribute to T cell activation?
By enhancing interactions between TCR and MHC-peptide complex
Which molecules are recognized by TCRs on T cells?
Peptide antigens presented by MHC molecules
What is the composition of the TCR with respect to chains?
1 α chain and 1 β chain
Which region of the TCR is responsible for recognizing specific antigens?
Hypervariable Complementarity-Determining Region (CDR) loops
What is the structure of the TCR when considering the heterodimer formation?
Heterodimer structure
Which event leads to the formation of an increasingly stable immune synapse in the T cell signaling pathway?
TCR-CD8 co-receptor interaction with MHC antigen
What is the function of CD4 and CD8 co-receptors in the T cell signaling pathway?
Recognition of specific antigens presented by MHC molecules
Which protein kinase phosphorylates tyrosine residues within the ITAMs upon TCR engagement?
ZAP-70
What is the main function of phosphorylated tyrosine residues within the ITAMs in the TCR signaling pathway?
Activate transcription factors
Following activation of transcription factors, what is the next step in the T cell signal pathway cascade?
Initiation of gene transcription
Which transcription factor is NOT activated by the downstream signaling proteins in the TCR signaling pathway?
STAT
What is the role of phosphorylated tyrosine residues within the ITAMs in recruiting other signaling proteins?
Serve as docking sites
Which molecules translocate to the nucleus and bind to specific DNA sequences in the T cell signal pathway?
Transcription factors
What do the expressed proteins contribute to in the T cell signal pathway?
T cell activation and function
Which proteins initiate a signaling cascade that amplifies and propagates the TCR signaling pathway?
Lck and ZAP-70 kinases
What event follows the binding of TCR and co-receptor to MHC antigen in the formation of an immune synapse?
Induction of T cell activation
What is the function of ZAP-70 in the T cell intracellular signaling pathway?
Phosphorylates tyrosine residues within ITAMs
Explore how T cells initiate a series of steps upon TCR engagement with specific peptide-MHC complexes, leading to downstream signaling cascades, transcription factor activation, and T cell activation. Learn about the role of T cell intracellular signaling in immune responses.
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