Three distinct classes of photoreceptors mediate the effects of UV-A/blue light (320–500 nm): the cryptochromes, phototropins and the ZEITLUPE (ZTL) family of proteins

TLS Online TPP Program

#Id: 9959

#XL - T Zoology

Wnt = wingless + integrated

TLS Online TPP Program

#Id: 9960

#XL - T Zoology

Wnt proteins are modified by linkage of a monounsaturated fatty acid, palmitoleic acid, to a serine in the middle of the protein.

TLS Online TPP Program

#Id: 9961

#XL - T Zoology

Lipid modifications of Wnt are catalyzed by the 

O-acetyltransferase Porcupine.

TLS Online TPP Program

#Id: 9962

#XL - T Zoology

Principal signaling receptor is Frizzled (Fz), contains 

7 TM α helices.

TLS Online TPP Program

#Id: 9963

#XL - T Zoology

The palmitoleate attached to the Wnt protein binds to a specific site on the Fz extracellular domain and stabilizes the Wnt-Fz complex.

TLS Online TPP Program

#Id: 9964

#XL - T Zoology

Wnt signal transduction pathways classify into:

1. Canonical wnt pathway (β-catenin dependent)

2. Noncanonical wnt pathways (β-catenin independent)