Reaction: Proinsulin binds zinc and calcium forming Proinsulin:zinc:calcium
- in pathway: Insulin processing
In the presence of high concentrations of zinc and calcium, proinsulin spontaneously forms soluble complexes containing 6 molecules of proinsulin, 2 zinc ions, and 1 calcium ion. Zinc Transporters ZnT5, ZnT6, and ZnT7 are found in the membrane of the Golgi in pancreatic cells (and also in many other cell types). They play a role in maintaining the high zinc concentration in the Golgi lumen and thus catalyze the formation of the proinsulin-zinc-calcium complex. Other transporters, such as the newly identified ZnT9 and ZnT10, may also be involved but this is presently unknown.
Reaction - small molecule participants:
Zn2+ [Golgi lumen]
Ca2+ [Golgi lumen]
Reactome.org reaction link: R-HSA-264976
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Reaction input - small molecules:
zinc(2+)
calcium(2+)
Reaction output - small molecules:
Reactome.org link: R-HSA-264976