Haldane’s rule: Hybrid sterility or hybrid inviability is often limited to the heterogametic sex. 

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.

TLS Online TPP Program

#Id: 9661

#Unit 4. Cell Communication and Cell Signaling

Activated RTKs and cytokine receptors promote PLCγ activity in two ways: 

By localizing PLCγ to the membrane

By phosphorylating PLCγ

TLS Online TPP Program

#Id: 9662

#Unit 4. Cell Communication and Cell Signaling

The SH2 domains of PLCγ bind to specific phosphotyrosines on the activated RTKs and cytokine receptors, thus positioning PLCγ close to PIP2.

TLS Online TPP Program

#Id: 9663

#Unit 4. Cell Communication and Cell Signaling

Kinase activity associated with receptor activation phosphorylates tyrosines on the bound PLCγ, enhancing its hydrolase activity.