The binding of insulin is communicated through the single TM helix of each beta subunit to the paired Tyr kinase domains inside the cell, activating them to phosphorylate each other on three Tyr residues (Tyr1158, Tyr1162, Tyr1163)

TLS Online TPP Program

#Id: 1759

#Unit 4. Cell Communication and Cell Signaling

Mechanisms to protect an individual from this sort of anti-self immune attack must exist, and they do, called as tolerance

TLS Online TPP Program

#Id: 1760

#Unit 4. Cell Communication and Cell Signaling

Self-tolerance involving both the elimination of immune cells that can react against self-antigens and active inhibition of immune responses.

TLS Online TPP Program

#Id: 1761

#Unit 4. Cell Communication and Cell Signaling

Self-reactive B cells can undergo receptor editing.

In this process, the antigen-specific V region is “edited” or switched for a different V-region gene segment via V(D)J recombination,

TLS Online TPP Program

#Id: 1762

#Unit 4. Cell Communication and Cell Signaling

Central tolerance deletes self-reactive T- or B-cell clones before the cells are allowed to mature. occurs in the primary lymphoid organs

TLS Online TPP Program

#Id: 1763

#Unit 4. Cell Communication and Cell Signaling

Peripheral tolerance, which renders some self-reactive lymphocytes in secondary lymphoid tissues inactive and generates others that actively inhibit immune responses against self

TLS Online TPP Program

#Id: 1764

#Unit 4. Cell Communication and Cell Signaling

Self antigens are not uncommon in the periphery, Two factors contribute to this:                                                                                                                             a. not all self a. antigens are expressed in the central lymphoid organs where negative selection occurs

b. there is a threshold requirement for affinity to self antigens before clonal deletion is triggered, allowing some weakly self-reactive clones to survive the weeding-out process.