GNAS
Function
Guanine nucleotide-binding proteins (G proteins) function as transducers in numerous signaling pathways controlled by G protein-coupled receptors (GPCRs). The alpha chain contains the guanine nucleotide binding site and alternates between an active, GTP-bound state and an inactive, GDP-bound state. Signaling by an activated GPCR promotes GDP release and GTP binding. The alpha subunit has a low GTPase activity that converts bound GTP to GDP, thereby terminating the signal. Both GDP release and GTP hydrolysis are modulated by numerous regulatory proteins. Signaling involves the activation of adenylyl cyclases, resulting in increased levels of the signaling molecule cAMP. GNAS functions downstream of several GPCRs, including beta-adrenergic receptors. XLas isoforms interact with the same set of receptors as Gnas isoforms.
Involvement in disease
GNAS hyperfunction
GNASHYP
This condition is characterized by increased trauma-related bleeding tendency, prolonged bleeding time, brachydactyly and intellectual disability. Both the XLas isoforms and the ALEX protein are mutated which strongly reduces the interaction between them and this may allow unimpeded activation of the XLas isoforms.
None
The disease is caused by variants affecting the gene represented in this entry.
ACTH-independent macronodular adrenal hyperplasia 1
AIMAH1
A rare adrenal defect characterized by multiple, bilateral, non-pigmented, benign, adrenocortical nodules. It results in excessive production of cortisol leading to ACTH-independent Cushing syndrome. Clinical manifestations of Cushing syndrome include facial and truncal obesity, abdominal striae, muscular weakness, osteoporosis, arterial hypertension, diabetes.
None
The disease is caused by variants affecting the gene represented in this entry.
Pseudohypoparathyroidism 1B
PHP1B
A disorder characterized by end-organ resistance to parathyroid hormone, hypocalcemia and hyperphosphatemia. Patients affected with PHP1B lack developmental defects characteristic of Albright hereditary osteodystrophy, and typically show no other endocrine abnormalities besides resistance to PTH.
None
The disease is caused by variants affecting the gene represented in this entry. Most affected individuals have defects in methylation of the gene. In some cases microdeletions involving the STX16 appear to cause loss of methylation at exon A/B of GNAS, resulting in PHP1B. Paternal uniparental isodisomy have also been observed.
Pseudohypoparathyroidism 1C
PHP1C
A disorder characterized by end-organ resistance to parathyroid hormone, hypocalcemia and hyperphosphatemia. It is commonly associated with Albright hereditary osteodystrophy whose features are short stature, obesity, round facies, short metacarpals and ectopic calcification.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the G-alpha family. G(s) subfamily.
Cellular localization
- Cell membrane
- Peripheral membrane protein
- Apical cell membrane
Alternative names
GNAS1, GNAS, Guanine nucleotide-binding protein G(s) subunit alpha isoforms XLas, Adenylate cyclase-stimulating G alpha protein, Extra large alphas protein, XLalphas