Duplicate gene and its parental copy can subfunctionalize so that each carries out only some of the roles that the ancestral gene performed. 

Ex- a duplicate of the β-hemoglobin locus is expressed in the fetus. 

TLS Online TPP Program

#Id: 10037

#Unit 4. Cell Communication and Cell Signaling

IL-1β receptors contain a globular TIR domain; binding of IL-1β to IL-1 receptors triggers dimerization

TLS Online TPP Program

#Id: 10038

#Unit 4. Cell Communication and Cell Signaling

After dimerization MyD88 proteins bind to the IL-1R through the TIRs, and facilitates the binding of many copies of the kinases IRAK4 and IRAK1 or IRAK2

TLS Online TPP Program

#Id: 10039

#Unit 4. Cell Communication and Cell Signaling

Activated IRAK1/2, binds TRAF6, an E3 ubiquitin ligase, to the signalsome, and promotes the formation of an extended 2-D lattice formed by TRAF6-TRAF6 interactions.

TLS Online TPP Program

#Id: 10040

#Unit 4. Cell Communication and Cell Signaling

TRAF6 catalyzes synthesis of long K-63-linked polyubiquitin chains that are covalently linked to TRAF6 itself.

TLS Online TPP Program

#Id: 10041

#Unit 4. Cell Communication and Cell Signaling

Rather than degradation, poly-K63 ubiquitin chains act as scaffolds that bind proteins that have a poly-K63 ubiquitin-binding domain

TLS Online TPP Program

#Id: 10042

#Unit 4. Cell Communication and Cell Signaling

Poly-K63 ubiquitin-binding domain containing proteins:

Protein kinase TAK1

NEMO subunit of the I-κB kinase