PMID: 23269669

 

    Legend: Gene, Sites

Title : Site-specific N-linked glycosylation of receptor guanylyl cyclase C regulates ligand binding, ligand-mediated activation and interaction with vesicular integral membrane protein 36 , VIP36

Abstract :

1. Guanylyl cyclase C ( GC-C ) is a multidomain , membrane-associated receptor guanylyl cyclase
2. GC-C is primarily expressed in the gastrointestinal tract, where it mediates fluid-ion homeostasis, intestinal inflammation, and cell proliferation in a cGMP-dependent manner, following activation by its ligands guanylin , uroguanylin , or the heat-stable enterotoxin peptide (ST)
3. GC-C is also expressed in neurons, where it plays a role in satiation and attention deficiency/hyperactive behavior
4. GC-C is glycosylated in the extracellular domain , and differentially glycosylated forms that are resident in the endoplasmic reticulum (130 kDa) and the plasma membrane (145 kDa) bind the ST peptide with equal affinity
5. When glycosylation of human GC-C was prevented, either by pharmacological intervention or by mutation of all of the 10 predicted glycosylation sites , ST binding and surface localization was abolished
6. Systematic mutagenesis of each of the 10 sites of glycosylation in GC-C , either singly or in combination, identified two sites that were critical for ligand binding and two that regulated ST-mediated activation
7. We also show that GC-C is the first identified receptor client of the lectin chaperone vesicular integral membrane protein , VIP36
8. Interaction with VIP36 is dependent on glycosylation at the same sites that allow GC-C to fold and bind ligand
9. Because glycosylation of proteins is altered in many diseases and in a tissue-dependent manner, the activity and/or glycan-mediated interactions of GC-C may have a crucial role to play in its functions in different cell types

Output (sent_index, trigger, protein, sugar, site):

• 0. glycosylation, , guanylyl cyclase C, -, -
• 4. glycosylated, , -, differentially glycosylated forms, -
• 4. glycosylated, , GC-C, -, domain
• 5. glycosylation, , -, -, sites
• 5. glycosylation, , GC-C, -, -
• 6. glycosylation, , GC-C, -, sites
• 8. glycosylation, , -, -, sites
• 9. glycosylation, , proteins, -, -

Output(Part-Of) (sent_index, protein, site):

• 1. Guanylyl cyclase C, multidomain
• 2. enterotoxin, peptide
• 6. GC-C, sites

*Output_Site_Fusion* (sent_index, protein, sugar, site):

 

Protein	NCBI ID	SENTENCE INDEX
GC-C	2984	1,2,3,4,5,6,7,8,9
VIP36	10960	0,7,8
guanylyl cyclase C	2984	0
Guanylyl cyclase C	2984	1
vesicular integral membrane protein 36	10960	0