Active Wnt signaling leads to the secretion of Notum.

TLS Online TPP Program

#Id: 7944

#Unit 2. Cellular Organization

Membrane and soluble secretory proteins synthesized on the rough ER undergo four principal modifications before they reach their final destinations: 

(1) Glycosylation in the ER and Golgi complex

(2) Formation of disulfide bonds in the ER

(3) Proper folding of polypeptide chains and assembly of multisubunit proteins in the ER

(4) Specific proteolytic cleavages in the ER, Golgi complex, and secretory vesicles

TLS Online TPP Program

#Id: 7945

#Unit 2. Cellular Organization

Glycoproteins

Proteins with attached carbohydrates

TLS Online TPP Program

#Id: 7946

#Unit 2. Cellular Organization

O-linked oligosaccharides

Carbohydrate chains in glycoproteins attached to the

hydroxyl group (-OH) in serine and threonine residues

TLS Online TPP Program

#Id: 7947

#Unit 2. Cellular Organization

N-linked oligosaccharides

carbohydrate chains attached to the amide nitrogen of asparagine

TLS Online TPP Program

#Id: 7948

#Unit 2. Cellular Organization

Biosynthesis of all N-linked oligosaccharides begins in the rough ER with a preformed oligosaccharide precursor containing 14 residues.

TLS Online TPP Program

#Id: 7949

#Unit 2. Cellular Organization

A branched oligosaccharide containing

3 glucose (Glc)

9 mannose (Man)

2 N-acetylglucosamine (GlcNAc)

Glc3Man9(GlcNAc)2