Apc

FIGURE 7-10 Early tyrosine phosphorylation events in T cell activation. On antigen recognition, there is clustering of TCR complexes with coreceptors (CD4, in this case). CD4-associated Lck becomes active and phosphorylates tyrosines in the ITAMs of CD3 and Z chains (A). ZAP-70 binds to the phosphotyrosines of the Z chains and is itself phosphorylated and activated. (The illustration shows one ZAP-70 molecule binding to two phosphotyrosines of one ITAM in the Z chain, but it is likely that initiation of a T cell response requires the assembly of multiple ZAP-70 molecules on each Z chain.) Active ZAP-70 then phosphorylates tyrosines on various adaptor molecules, such as LAT (B). The adaptors become docking sites for cellular enzymes such as PLCyl and exchange factors that activate Ras and other small G proteins upstream of MAP kinases (C), and these enzymes activate various cellular responses.

Phosphorylation and activation of PLCyl

Activation of Ras, MAPK pathways

FIGURE 7-10 Early tyrosine phosphorylation events in T cell activation. On antigen recognition, there is clustering of TCR complexes with coreceptors (CD4, in this case). CD4-associated Lck becomes active and phosphorylates tyrosines in the ITAMs of CD3 and Z chains (A). ZAP-70 binds to the phosphotyrosines of the Z chains and is itself phosphorylated and activated. (The illustration shows one ZAP-70 molecule binding to two phosphotyrosines of one ITAM in the Z chain, but it is likely that initiation of a T cell response requires the assembly of multiple ZAP-70 molecules on each Z chain.) Active ZAP-70 then phosphorylates tyrosines on various adaptor molecules, such as LAT (B). The adaptors become docking sites for cellular enzymes such as PLCyl and exchange factors that activate Ras and other small G proteins upstream of MAP kinases (C), and these enzymes activate various cellular responses.

Was this article helpful?

0 0
How To Bolster Your Immune System

How To Bolster Your Immune System

All Natural Immune Boosters Proven To Fight Infection, Disease And More. Discover A Natural, Safe Effective Way To Boost Your Immune System Using Ingredients From Your Kitchen Cupboard. The only common sense, no holds barred guide to hit the market today no gimmicks, no pills, just old fashioned common sense remedies to cure colds, influenza, viral infections and more.

Get My Free Audio Book


Post a comment