The α-amanitin binding site is beneath a “bridge helix” extending across the cleft between the two largest pol II subunits, Rpb1 and Rpb2

TLS Online TPP Program

#Id: 9980

#Unit 4. Cell Communication and Cell Signaling

Notum, a hydrolase that associates with glypican and then cleaves off Wnt’s attached lipids in a process of deacylation or delipidation.

TLS Online TPP Program

#Id: 9981

#Unit 4. Cell Communication and Cell Signaling

Delipidation process reduces Wnt signaling, creates a negative feedback mechanism for preventing excessive Wnt signaling.

TLS Online TPP Program

#Id: 9982

#Unit 4. Cell Communication and Cell Signaling

Frizzled receptor possesses a unique hydrophobic cleft adapted to interact with lipidated Wnts, a binding conformation mimicked in Notum’s structure as well.

TLS Online TPP Program

#Id: 9983

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9984

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9985

#Unit 4. Cell Communication and Cell Signaling

Antagonists of Wnt:

Secreted frizzled-related protein (Sfrp)

Wnt inhibitory factor (Wif)

Dickkopf (Dkk) family