The B Cell Receptor (BCR) Complex and the Signaling Cascades

question 9

Multiple Choice

The B cell receptor (BCR) complex and the signaling cascades to which it is linked share many similarities with the T cell receptor (TCR) complex and its linked signaling cascades. Which of the following comparisons between BCR and TCR signaling is NOT true?

• A)There are ITAMs in the cytoplasmic tails of CD3 in the TCR complex and in the cytoplasmic tails of Igα and Igβ in the BCR complex.
• B)The cytoplasmic tails of membrane Ig and TCR αβ antigen receptors are very short and lack intrinsic signaling functionality.
• C)Early signaling events induced by antigen binding to both BCR and TCR involve both Src family and Zap-70 family protein tyrosine kinases.
• D)Phospholipase C-mediated generation of IP₃ and DAG occurs downstream of both BCR and TCR signaling.
• E)CD4/CD8 coreceptors in T cells and the CR2 coreceptor in B cells both enhance responses to antigen by a PI3 kinase-dependent mechanism.

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