Wnt signalling

Question 1

what type of signalling is wnt signalling an example of?

Answer 1

Paracrine signalling

Question 2

what is the canonical wnt signalling pathway

Answer 2

Beta-Catenin signalling pathway

Question 3

what are the membrane receptors that Wnt binds to

Answer 3

Frizzled receptor and LRP6 dimerize upon wnt binding

Question 4

how many wnt genes are there in humans?

Answer 4

19

Question 5

what is the destruction complex?

Answer 5

destruction complex is a protein complex that forms in the absence of wnt. the beta-cateinin destruction complex ensures that target genes cannot be activated by beta-catenin by phosphorylating it and labelling it for destruction.

Question 6

what are the proteins involved in the destruction complex?

Answer 6

GSK3Beta(Glycogen Synthase Kinase 3B), CK1Alpha( Casein Kinase1a), APC( Adenomatous Polyposis Coli) and Scaffold protein Axin holding it all together

Question 7

what component of the destruction complex mutates in colorectal cancer?

Answer 7

APC mutation found in 80% of colorectal cancers

Question 8

what is CSK1a role in the destruction complex?

Answer 8

CSK1a adds the primary phosphate to Ser45 priming it for GSK3B

Question 9

what does GSK3B do in the destruction complex?

Answer 9

GSK3B phosphoralyses Thr 41,Ser 37 and Ser 33 labelling beta-catenin for destruction

Question 10

what is the name of the protein that adds a Ub tag to Beta-catenin for destruction by the proteosome?

Answer 10

Beta-Trpc

Question 11

how is the wnt/B-catenin pathway regulated?

Answer 11

Alternate assembly of multiprotein complexes

Question 12

what are the three points at which the wnt/B-catenin pathway are controlled?

Answer 12

Receptor dimerization complex at the cell membrane, B-catenin destruction complex in the cytoplasm, Transcription factor complex in the nucleus.