Binding of the ligand to the receptor causes the receptor to change from an inactive conformation (R) to an active conformation (R*). Only the active R* conformation of the receptor can trigger the signal transduction pathway.

TLS Online TPP Program

#Id: 1729

#Unit 4. Cell Communication and Cell Signaling

FcεRI pathways are phosphorylations, multiple phosphatases, such as SHPs, SHIPs, and PTEN, play an important role in dampening receptor signaling.

TLS Online TPP Program

#Id: 1730

#Unit 4. Cell Communication and Cell Signaling

Lyn, can play a negative as well as a positive role in FcεRI signaling by phosphorylating and activating the inhibitory FcεRIIB.

TLS Online TPP Program

#Id: 1731

#Unit 4. Cell Communication and Cell Signaling

FcεRI signalling through Lyn and Syk kinases also activates E3 ubiquitin ligases, including c-Cbl. Cbl ubiquitinylates Lyn and Syk, as well as FcεRI itself, triggering their degradation.

TLS Online TPP Program

#Id: 1732

#Unit 4. Cell Communication and Cell Signaling

The early response occurs within minutes of allergen exposure and results from the release of histamine, leukotrienes, and prostaglandins from local mast cells.

TLS Online TPP Program

#Id: 1733

#Unit 4. Cell Communication and Cell Signaling

Eosinophils play a principal role in the late-phase reaction.

TLS Online TPP Program

#Id: 1734

#Unit 4. Cell Communication and Cell Signaling

There Are Several Categories of Type I Hypersensitivity Reactions

1. Systemic Anaphylaxis

2. Localized Hypersensitivity Reactions