multi complex disassembly linked Flashcards
what are WNT receptors
7 transmembrane receptors but not G protein coupled receptors
how does WNT cause changes in transcription
it activates the TCF transcription factor
in the absence of WNT, what is beta catenin held in a complex with
beta catenin- axin- GSK3- APC
what is the role of GSK3
it phosphorylates beta catenin which degrades it and stops it binding to TCF
another name for WNT receptors
frazzled (FZ) receptor
what happens with WNT binds to its receptor
GSK3 phosphorylates LRP
this permits axin binding to LRP
what does actin binding to LRP cause
complex disassembly, beta catenin is no longer phosphorylated
it can move to the nucleus and bind TCF
what is the purpose of Hh (hedgehog) signalling
transmits info to embryonic cells for differentiation
where is Smo kept when Hh is absent
in internal vesicles guarded by Ptc (patched receptor)
where is Ci kept when Hh is absent
in a microtubule bound complex guarded by Cos2 and Fu
what phosphorylates Ci
PKA,CK1, GSK3
what degrades phosphorylated Ci and what happens after
degraded by Slimb into Ci75 which travels to nucleus to prevent transcription
what happens to Smo when Hh is present
Hh binds to Ptc which lets Smo escape to the plasma membrane where it is phosphorylated by PKA and CK1
what happens to the complex when Hh is present
Cos2 and Fu are phosphorylated and form a complex with Smo
Ci escapes from the disassembled complex
how does Ci mediate transcription
it moves to the nucleus and forms a complex with CRB to mediate transcription
