Signaling Through Immune System Receptors

1
Chapter 6 Signaling Through Immune System
Receptors
Ig, TCR, cytokine receptors signal transduction
is the change of a signal from one form to
another (i.e., passing information along in
different forms)
2
Two types of receptors that signal through
protein kinases
Kinaseinactive
Kinase
active
3
The cytoplasmic tail of the BCR does not have
catalytic or signaling activity. Instead, BCRs
are associated with two invariant chains, Iga and
Igb. Aggregation or conformational changes in the
Ig molecule causes changes in the Iga and Igb
heterodimer that allow it to signal the inside of
the cell that antigen has been bound by the
surface Ig on the outside of the cell
Immunoreceptor tyrosine-based activation motif
(ITAM)
4
Similar to BCR, the TCR alone cannot signal the T
cell that it has bound antigen The TCR is always
associated with CD3 (g,d,e) and z (zeta) chain.
These molecules are involved in signaling the T
cell when it engages antigen in its TCR
The TCR plus CD3 is referred to as the TCR complex
5
CD4
What cell(s) has these receptors on its surface?
What is recognized by these receptors?
6
Clustering of BCRs initiates signaling into the B
cells (receptor aggregation) aggregational
signaling
next
Slide 7
In nature, BCR aggregation occurs when an epitope
is repeated on one molecule (polymers) or on a
surface (e.g., surface of bacteria or virus).
Also, conformational signaling antigen binding
to the receptor changes the conformation (3D
structure) of the receptor so it gains or looses
reactivity this occurs when epitopes do not
repeat on an antigen
7
Slide 6
8
(No Transcript)
9
(No Transcript)