Immunity: Chapter 05 Activation and Effector Actions of T Cells

Which of the following contribute(s) to the amplification of signaling through the TCR?

	a)	Clustering of signaling components.
	b)	Retention of Csk in the lipid raft.
	c)	The existence of large numbers of ITAMs on the signaling chains of the TCR.
	d)	Strong adhesion to the dendritic cell stimulated by initial TCR signaling.
CorrectWrong: a, c and d are correct.Your answer has been saved.

Which of the following statements are true?

	a)	LFA-1 expressed on T cells binds to ICAM-1 on dendritic cells.
	b)	The tyrosine kinase Csk is activated on signaling through the TCR.
	c)	Cbl family ubiquitin ligases are recruited to the TCR by phosphorylation of ITAMs and tag the TCR for internalization and destruction.
	d)	The phosphatase CD45 is recruited to the scaffold protein PAG1 on phosphorylation of PAG1.
	e)	In the immunological synapse-the specialized zone of contact between a T cell and a dendritic cell (or target cell)-a central zone, known as the c-SMAC, contains the TCR, coreceptors, B7, and CD2 adhesion molecules.
	f)	The activating phosphatase CD45 is contained in the outer ring of the immunological synapse, the p-SMAC.
	g)	The organization of the immunological synapse requires cytoskeletal reorganization.
	h)	Signaling occurs mainly outside the central zone of the immunological synapse.
CorrectWrong: a, c, e, g and h are true.Your answer has been saved.

Activation of the Src kinase Lck, which is critical to the initiation of signaling from the TCR, is controlled by a combination of activating and inhibitory phosphate groups on tyrosines. Which of the following molecules contribute(s) to its feedback inhibition by executing or promoting the addition of inhibitory phosphate groups or removal of activating phosphate groups?

	a)	The phosphatase CD45.
	b)	The phosphatase PEP.
	c)	The tyrosine kinase Csk.
	d)	Phosphorylation of PAG1.
CorrectWrong: b, c, and d are correct.Your answer has been saved.