Phosphorylation of RegA is mediated by sensor histidine kinases/phosphatases which either phosphorylate or dephosphorylate themselves on a histidine residue when a signal molecule binds to their sensor domain.

TLS Online TPP Program

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#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

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#Unit 4. Cell Communication and Cell Signaling

Poly-K63 ubiquitin-binding domain containing proteins:

Protein kinase TAK1

NEMO subunit of the I-κB kinase

TLS Online TPP Program

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#Unit 4. Cell Communication and Cell Signaling

Poly-K63 ubiquitin chain brings TAK1 kinase and β subunit of I-κB

kinase, into close proximity so that TAK1 can phosphorylate and activate I-κB kinase

TLS Online TPP Program

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#Unit 4. Cell Communication and Cell Signaling

In Notch/Delta pathway, 

signaling molecule is Delta, an integral membrane protein bound to the surface of the signaling cell.

TLS Online TPP Program

#Id: 10045

#Unit 4. Cell Communication and Cell Signaling

In Notch/Delta pathway, 

Notch is receptor protein, on a neighboring responding cell

TLS Online TPP Program

#Id: 10046

#Unit 4. Cell Communication and Cell Signaling

In the absence of Delta, 

TM subunit of Notch on the surface of a responding cell is non-covalently associated with its extracellular subunit; extracellular domain is folded