For most, but not all, RTKs, the weakly active kinase in each subunit is phosphorylate a key tyrosine in the activation loop of the other subunit (trans-phosphorylation)

TLS Online TPP Program

#Id: 9655

#Unit 4. Cell Communication and Cell Signaling

Feedback regulation by MAP Kinase

Phosphorylation of threonine residue in HER1 decreases the ability of the receptor kinase to become fully active.

TLS Online TPP Program

#Id: 9656

#Unit 4. Cell Communication and Cell Signaling

Feedback regulation by MAP Kinase

Active MAP kinase phosphorylates Raf on multiple sites, reducing its association with Ras.

TLS Online TPP Program

#Id: 9657

#Unit 4. Cell Communication and Cell Signaling

Negative feedback regulation by MAP Kinase

activated MAP kinase triggers an increase in the expression of dual-specificity phosphatases (DUSPs), particularly DUSP6.

TLS Online TPP Program

#Id: 9658

#Unit 4. Cell Communication and Cell Signaling

Hormonal stimulation of GPCR leads to the activation of PLC (IP3/DAG pathway).

TLS Online TPP Program

#Id: 9659

#Unit 4. Cell Communication and Cell Signaling

GPCRs specifically activate the β isoform of PLC (PLCβ)

TLS Online TPP Program

#Id: 9660

#Unit 4. Cell Communication and Cell Signaling

Many RTKs and cytokine receptors specifically activate the γ isoform (PLCγ), which contains an SH2 domain.