In the absence of insulin, the extracellular domain adopts a symmetric inverted U-shaped conformation. 

TLS Online TPP Program

#Id: 1755

#Unit 4. Cell Communication and Cell Signaling

Presentation of nonpeptide antigens derived from pathogens involves the nonclassical class I–like CD1 molecule

TLS Online TPP Program

#Id: 1756

#Unit 4. Cell Communication and Cell Signaling

Class I presentation requires internal synthesis of virus protein, as shown by the requirement that the target cell be infected by live virus, and by the inhibition of class I presentation observed when protein synthesis was blocked by the inhibitor emetine.

TLS Online TPP Program

#Id: 1757

#Unit 4. Cell Communication and Cell Signaling

Class II presentation can occur with either live or replication-incompetent virus; protein synthesis inhibitors had no effect, indicating that new protein synthesis is not a necessary condition of class II presentation.

TLS Online TPP Program

#Id: 1758

#Unit 4. Cell Communication and Cell Signaling

Class II, but not class I, presentation is inhibited by treatment of the cells with an agent that blocks endocytic processing within the cell (chloroquine).

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.