Zinc Transporters Flashcards
What did Cragg et al. show regarding ZnT5 localisation?
- Using antibodies found ZnT5 on apical surface of jejunum and dudodenum.
- Use of WB - co-purified ZnT5 with apical membrane (when isolated only apical - found enriched in protein).
- Caco-2 cells - confocal microscopy –> little found in nuclear sections but at top lots.
- Alkaline phosphatase is present on apical surface and ZnT5 shown to colocalise.
What happens to human and mice with ZIP4 deficiencies?
Humans - acrodermatitis enteropathica = mental disturbance / lack of growth
Mice - haploinsufficiency - brain outside skull, skeletal malformities.
KOs - males die within a week due to dedifferentiatedt intestines.
What are the roles for zinc in prostate?
Inhibits m-aconitase to allow citrate accumulation in semen.
Aids sperm movement
Inhibits kallikrein-3 - breaks down semenogelins in acid pH of vagina - protects from harming prostate gland itself.
Antimicrobial in prostatic fluid.
What is mammary gland?
Network of branched ductal structures which terminate at acinar units. Each acini lined with mammary epithelial cells which transfer nutrients to milk.
How is the histology of the mammary glands altered during pregnancy and lactation?
MMPs = zinc dependent enzymes.
During lactation and pregnancy - MMP3 and 7 expression increases.
On cessation - MMP2, 3 and 11 upegulated.
What are the symptoms of transient neonatal zinc deficiency?
~75% reduction in milk [Zn] –> severe dermatitis and alpecia.
How does zinc affect alpha cells and insulin release?
In response to glucose - hexamers (have 2 Zn bound each) releases into intraislet portal circulation. Zn dissociates, binds and opens ATP dependent k+ channels on cells –> hyperpolarisation cells, inhibits VD calcium channels and blocks glucagon release.
