Effect of zinc binding residues in growth hormone (GH) and altered intracellular zinc content on regulated GH secretion.

Petkovic, Vibor; Miletta, Maria Consolata; Eblé, Andrée; Iliev, Daniel I.; Binder, Gerhard; Flück, Christa; Mullis, Primus-Eugen (2013). Effect of zinc binding residues in growth hormone (GH) and altered intracellular zinc content on regulated GH secretion. Endocrinology, 154(11), pp. 4215-4225. Endocrine Society 10.1210/en.2013-1089

Full text not available from this repository. (Request a copy)

Endocrine cells store hormones in concentrated forms (aggregates) in dense-core secretory granules that are released upon appropriate stimulation. Zn(2+) binding to GH through amino acid residues His18, His21, and Glu174 are essential for GH dimerization and might mediate its aggregation and storage in secretory granules. To investigate whether GH-1 gene mutations at these positions interfere with this process, GH secretion and intracellular production were analyzed in GC cells (rat pituitary cell line) transiently expressing wt-GH and/or GH Zn mutant (GH-H18A-H21A-E174A) in forskolin-stimulated vs nonstimulated conditions. Reduced secretion of the mutant variant (alone or coexpressed with wt-GH) compared with wt-GH after forskolin stimulation was observed, whereas an increased intracellular accumulation of GH Zn mutant vs wt-GH correlates with its altered extracellular secretion. Depleting Zn(2+) from culture medium using N,N,N',N'-tetrakis(2-pyridylemethyl)ethylenediamine, a high-affinity Zn(2+) chelator, led to a significant reduction of the stimulated wt-GH secretion. Furthermore, externally added Zn(2+) to culture medium increased intracellular free Zn(2+) levels and recovered wt-GH secretion, suggesting its direct dependence on free Zn(2+) levels after forskolin stimulation. Confocal microscopy analysis of the intracellular secretory pathway of wt-GH and GH Zn mutant indicated that both variants pass through the regulated secretory pathway in a similar manner. Taken together, our data support the hypothesis that loss of affinity of GH to Zn(2+) as well as altering intracellular free Zn(2+) content may interfere with normal GH dimerization (aggregation) and storage of the mutant variant (alone or with wt-GH), which could possibly explain impaired GH secretion.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Gynaecology, Paediatrics and Endocrinology (DFKE) > Clinic of Paediatric Medicine
04 Faculty of Medicine > Department of Gynaecology, Paediatrics and Endocrinology (DFKE) > Clinic of Paediatric Medicine > Endocrinology/Metabolic Disorders
04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Unit Childrens Hospital > Forschungsgruppe Endokrinologie / Diabetologie / Metabolik (Pädiatrie)

UniBE Contributor:

Petkovic, Vibor; Miletta, Maria Consolata; Eblé, Andrée; Flück, Christa and Mullis, Primus-Eugen

Subjects:

600 Technology > 610 Medicine & health
500 Science > 570 Life sciences; biology

ISSN:

0013-7227

Publisher:

Endocrine Society

Language:

English

Submitter:

Christa Emma Flück Pandey

Date Deposited:

12 Jun 2014 10:43

Last Modified:

12 Jun 2014 10:43

Publisher DOI:

10.1210/en.2013-1089

PubMed ID:

23970781

URI:

https://boris.unibe.ch/id/eprint/45682

Actions (login required)

Edit item Edit item
Provide Feedback