scholarly journals A Disruptive Mutation in Exon 3 of the GNAS Gene with Albright Hereditary Osteodystrophy, Normocalcemic Pseudohypoparathyroidism, and Selective Long Transcript Variant Gsα-L Deficiency

2007 ◽  
Vol 92 (5) ◽  
pp. 1764-1768 ◽  
Author(s):  
Susanne Thiele ◽  
Ralf Werner ◽  
Wiebke Ahrens ◽  
Ute Hoppe ◽  
Christine Marschke ◽  
...  
Keyword(s):  
Protein Level ◽  
Splice Variants ◽  
Stop Codon ◽  
Erythrocyte Membranes ◽  
Protein Activity ◽  
Α Subunit ◽  
Biallelic Expression ◽  
Albright Hereditary Osteodystrophy ◽  
Gnas Gene ◽  
Type Ia

Abstract Objective: The GNAS gene encodes the α-subunit of stimulatory G proteins, which play a crucial role in intracellular signal transduction of peptide and neurotransmitter receptors. In addition to transcript variants that differ in their first exon due to different promoters, there are two long (Gsα-L) and two short (Gsα-S) splice variants, created by alternative splicing. Heterozygous inactivating maternally inherited mutations of GNAS lead to a phenotype in which Albright hereditary osteodystrophy is associated with pseudohypoparathyroidism type Ia. Methods and Results: The GNAS gene of a 10-yr-old girl with brachymetacarpia, mental retardation, normocalcemic pseudohypoparathyroidism, and hypothyroidism was investigated. We found a heterozygous insertion of an adenosine in exon 3 altering codon 85 and leading to a frame shift inducing a stop codon in exon 4. Molecular studies of cDNA from blood RNA demonstrated normal, biallelic expression of Gsα-S transcripts, whereas expression of Gsα-L transcripts from the maternal allele was reduced. Immunoblot analysis revealed a reduced Gsα-L protein level to about 50%, whereas the protein level of Gsα-S was unaltered. Furthermore, the Gsα protein activity in erythrocyte membranes was diminished to about 75% of normal. Both the reduced activity and the mutation were also found in the mother and the affected younger brother. Conclusion: This report demonstrates the first evidence for a pathogenic mutation in exon 3 of the GNAS gene. The mutation is associated with a phenotype of Albright hereditary osteodystrophy and pseudohypoparathyroidism type Ia due to selective deficiency of Gsα-L and a partial reduction of Gsα activity.

Receptor-Cyclase Coupling Protein in Erythrocytes of Patients with Essential Hypertension

1984 ◽  
Vol 67 (1) ◽  
pp. 111-115 ◽  
Author(s):  
Zvi Farfel ◽  
Adrian Iaina ◽  
Haskel Eliahou ◽  
Zohara Cohen
Keyword(s):  
Essential Hypertension ◽  
Antihypertensive Drugs ◽  
Normal Subjects ◽  
Erythrocyte Membranes ◽  
Adrenergic System ◽  
Protein Activity ◽  
N Protein ◽  
Type Ia ◽  
Coupling Protein

1. In order to define the alteration of the function of the adrenergic system in hypertension, we studied directly the receptor-cyclase coupling protein (N protein), which is one of the components of the enzyme adenylate cyclase. 2. N protein was determined in erythrocyte membranes of patients with essential hypertension and normal subjects, with a complementation assay in vitro. Fifteen normal subjects and 18 patients with essential hypertension (eight untreated and ten treated with β-adrenoreceptor blocking drugs alone or in combination with other antihypertensive drugs), and two patients with pseudohypoparathyroidism type Ia (known to have deficient N protein activity), were studied. 3. Erythrocyte N protein activities in the various groups expressed as percentages of the means ± sd of normals were: normal subjects 100 ± 13.7, untreated hypertensive 108.9 ± 20.4, treated hypertensive 104.3 ± 11.3 and pseudohypoparathyroidism type Ia 43%. 4. The difference between N protein activity in the hypertensive patients and normals was not statistically significant. We suggest that the molecular basis for the altered sympathetic responsiveness in essential hypertension may reside in other components of the cyclic AMP protein kinase effector system.

scholarly journals Coordinated control of sensitivity by two splice variants of Gαo in retinal ON bipolar cells

2010 ◽  
Vol 136 (4) ◽  
pp. 443-454 ◽  
Author(s):  
Haruhisa Okawa ◽  
Johan Pahlberg ◽  
Fred Rieke ◽  
Lutz Birnbaumer ◽  
Alapakkam P. Sampath
Keyword(s):  
G Protein ◽  
Single Photon ◽  
Splice Variants ◽  
Light Response ◽  
Light Sensitivity ◽  
Bipolar Cells ◽  
Protein Activity ◽  
Α Subunit ◽  
Coordinated Action ◽  
Rod Bipolar Cells

The high sensitivity of scotopic vision depends on the efficient retinal processing of single photon responses generated by individual rod photoreceptors. At the first synapse in the mammalian retina, rod outputs are pooled by a rod “ON” bipolar cell, which uses a G-protein signaling cascade to enhance the fidelity of the single photon response under conditions where few rods absorb light. Here we show in mouse rod bipolar cells that both splice variants of the Go α subunit, Gαo1 and Gαo2, mediate light responses under the control of mGluR6 receptors, and their coordinated action is critical for maximizing sensitivity. We found that the light response of rod bipolar cells was primarily mediated by Gαo1, but the loss of Gαo2 caused a reduction in the light sensitivity. This reduced sensitivity was not attributable to the reduction in the total number of Go α subunits, or the altered balance of expression levels between the two splice variants. These results indicate that Gαo1 and Gαo2 both mediate a depolarizing light response in rod bipolar cells without occluding each other’s actions, suggesting they might act independently on a common effector. Thus, Gαo2 plays a role in improving the sensitivity of rod bipolar cells through its action with Gαo1. The coordinated action of two splice variants of a single Gα may represent a novel mechanism for the fine control of G-protein activity.

scholarly journals Molecular Definition of Pseudohypoparathyroidism Variants

2021 ◽  
Author(s):  
Harald Jüppner
Keyword(s):  
Splice Variants ◽  
Renal Tubules ◽  
Epigenetic Changes ◽  
Biallelic Expression ◽  
Developmental Abnormalities ◽  
Stimulatory G Protein ◽  
Type Ia ◽  
Hormonal Resistance ◽  
Disease Variant ◽  
Definition Of

Abstract Pseudohypoparathyroidism (PHP) and pseudopseudohypoparathyroidism (PPHP) are caused by mutations and/or epigenetic changes at the complex GNAS locus on chromosome 20q13.3 that undergoes parent-specific methylation changes at several differentially methylated regions (DMRs). GNAS encodes the alpha-subunit of the stimulatory G protein (Gsα) and several splice variants thereof. PHP type Ia (PHP1A) is caused by heterozygous inactivating mutations involving the maternal exons 1-13. Heterozygosity of these maternal GNAS mutations cause PTH-resistant hypocalcemia and hyperphosphatemia because paternal Gsα expression is suppressed in certain organs thus leading to little or no Gsα protein in the proximal renal tubules and other tissues. Besides biochemical abnormalities, PHP1A patients show developmental abnormalities, referred to as Albright’s hereditary osteodystrophy (AHO). Some, but not all of these AHO features are encountered also in patients affected by PPHP, who carry paternal Gsα-specific mutations and typically show no laboratory abnormalities. Autosomal dominant PHP type Ib (AD-PHP1B) is caused by heterozygous maternal deletions within GNAS or STX16, which are associated with loss of methylation at the A/B DMR alone or at all maternally methylated GNAS exons. Loss of methylation of exon A/B and the resulting biallelic expression of A/B transcript reduces Gsα expression thus leading to hormonal resistance. Epigenetic changes at all differentially methylated GNAS regions are also observed in sporadic PHP1B, which is the most frequent PHP1B variant. However, this disease variant remains unresolved at the molecular level, except for rare cases with paternal uniparental isodisomy or heterodisomy of chromosome 20q (patUPD20q).

scholarly journals Large Conductance Ca2+-Activated K+ Channel (BKCa) α-Subunit Splice Variants in Resistance Arteries from Rat Cerebral and Skeletal Muscle Vasculature

PLoS ONE ◽  
2014 ◽  
Vol 9 (6) ◽  
pp. e98863 ◽  
Author(s):  
Zahra Nourian ◽  
Min Li ◽  
M. Dennis Leo ◽  
Jonathan H. Jaggar ◽  
Andrew P. Braun ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Splice Variants ◽  
K Channel ◽  
Resistance Arteries ◽  
Α Subunit

Distribution and oligomeric association of splice forms of Na+-K+-ATPase regulatory γ-subunit in rat kidney

2002 ◽  
Vol 282 (3) ◽  
pp. F393-F407 ◽  
Author(s):  
Elena Arystarkhova ◽  
Randall K. Wetzel ◽  
Kathleen J. Sweadner
Keyword(s):  
Splice Variants ◽  
Rat Kidney ◽  
Thick Ascending Limb ◽  
Outer Medulla ◽  
Α Subunit ◽  
Proximal Tubule Cells ◽  
Γ Subunit ◽  
Outer Stripe ◽  
A Minor ◽  
Splice Forms

Renal Na+-K+-ATPase is associated with the γ-subunit (FXYD2), a single-span membrane protein that modifies ATPase properties. There are two splice variants with different amino termini, γa and γb. Both were found in the inner stripe of the outer medulla in the thick ascending limb. Coimmunoprecipitation with each other and the α-subunit indicated that they were associated in macromolecular complexes. Association was controlled by ligands that affect Na+-K+-ATPase conformation. In the cortex, the proportion of the γb-subunit was markedly lower, and the γa-subunit predominated in isolated proximal tubule cells. By immunofluorescence, the γb-subunit was detected in the superficial cortex only in the distal convoluted tubule and connecting tubule, which are rich in Na+-K+-ATPase but comprise a minor fraction of cortex mass. In the outer stripe of the outer medulla and for a short distance in the deep cortex, the thick ascending limb predominantly expressed the γb-subunit. Because different mechanisms maintain and regulate Na+ homeostasis in different nephron segments, the splice forms of the γ-subunit may have evolved to control the renal Na+ pump through pump properties, gene expression, or both.

scholarly journals An Alternative Splice Variant of HIPK2 with Intron Retention Contributes to Cytokinesis

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 484 ◽  
Author(s):  
Veronica Gatti ◽  
Manuela Ferrara ◽  
Ilaria Virdia ◽  
Silvia Matteoni ◽  
Laura Monteonofrio ◽  
...  
Keyword(s):  
Cell Division ◽  
Stress Response ◽  
Alternative Splice ◽  
Functional Activity ◽  
Splice Variant ◽  
Splice Variants ◽  
Stop Codon ◽  
Cellular Stress Response ◽  
Dependent Manner ◽  
Western Blots

HIPK2 is a DYRK-like kinase involved in cellular stress response pathways, development, and cell division. Two alternative splice variants of HIPK2, HIPK2-FL and HIPK2-Δe8, have been previously identified as having different protein stability but similar functional activity in the stress response. Here, we describe one additional HIPK2 splice variant with a distinct subcellular distribution and functional activity in cytokinesis. This novel splice variant lacks the last two exons and retains intron13 with a stop codon after 89 bp of the intron, generating a short isoform, HIPK2-S, that is detectable by 2D Western blots. RT-PCR analyses of tissue arrays and tumor samples show that HIPK2-FL and HIPK2-S are expressed in normal human tissues in a tissue-dependent manner and differentially expressed in human colorectal and pancreatic cancers. Gain- and loss-of-function experiments showed that in contrast to HIPK2-FL, HIPK2-S has a diffuse, non-speckled distribution and is not involved in the DNA damage response. Rather, we found that HIPK2-S, but not HIPK2-FL, localizes at the intercellular bridge, where it phosphorylates histone H2B and spastin, both required for faithful cell division. Altogether, these data show that distinct human HIPK2 splice variants are involved in distinct HIPK2-regulated functions like stress response and cytokinesis.

Cloning and functional studies of splice variants of the α-subunit of the amiloride-sensitive Na+ channel

1998 ◽  
Vol 274 (4) ◽  
pp. C1081-C1089 ◽  
Author(s):  
J. Kevin Tucker ◽  
Kaichiro Tamba ◽  
Young-Jae Lee ◽  
Li-Ling Shen ◽  
David G. Warnock ◽  
...  
Keyword(s):  
Amino Acid ◽  
Splice Variants ◽  
Extracellular Domain ◽  
Na Channel ◽  
Wild Type ◽  
Rt Pcr ◽  
Α Subunit ◽  
Functional Studies ◽  
Human Lung Cell Line ◽  
Lung Cell Line

The α-subunit of the amiloride-sensitive epithelial Na+ channel (αENaC) is critical in forming an ion conductive pore in the membrane. We have identified the wild-type and three splice variants of the human αENaC (hαENaC) from the human lung cell line H441, using RT-PCR. These splice variants contain various structures in the extracellular domain, resulting in premature truncation (hαENaCx), 19-amino acid deletion (hαENaC−19), and 22-amino acid insertion (hαENaC+22). Wild-type hαENaC and splice variants were functionally characterized in Xenopus oocytes by coexpression with hENaC β- and γ-subunits. Unlike wild-type hαENaC, undetectable or substantially reduced amiloride-sensitive currents were observed in oocytes expressing these splice variants. Wild-type hαENaC was the most abundantly expressed hαENaC mRNA species in all tissues in which its expression was detected. These findings indicate that the extracellular domain is important to generate structural and functional diversity of hαENaC and that alternative splicing may play a role in regulating hENaC activity.

scholarly journals Alternative splice variants of AID are not stoichiometrically present at the protein level in chronic lymphocytic leukemia

2014 ◽  
Vol 44 (7) ◽  
pp. 2175-2187 ◽  
Author(s):  
Stefan Rebhandl ◽  
Michael Huemer ◽  
Nadja Zaborsky ◽  
Franz Josef Gassner ◽  
Kemal Catakovic ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Alternative Splice ◽  
Protein Level ◽  
Splice Variants ◽  
Lymphocytic Leukemia ◽  
Alternative Splice Variants

scholarly journals The KlGpa1 Gene Encodes a G-Protein α Subunit That Is a Positive Control Element in the Mating Pathway of the Budding Yeast Kluyveromyces lactis

2001 ◽  
Vol 183 (1) ◽  
pp. 229-234 ◽  
Author(s):  
Alma L. Saviñón-Tejeda ◽  
Laura Ongay-Larios ◽  
Julián Valdés-Rodrı́guez ◽  
Roberto Coria
Keyword(s):  
G Protein ◽  
Stop Codon ◽  
Kluyveromyces Lactis ◽  
Control Element ◽  
Wild Type ◽  
Pheromone Response ◽  
Α Subunit ◽  
Pheromone Response Pathway ◽  
G Protein Α Subunit ◽  
Mating Pathway

ABSTRACT The cloning of the gene encoding the KlGpa1p subunit was achieved by standard PCR techniques and by screening a Kluyveromyces lactis genomic library using the PCR product as a probe. The full-length open reading frame spans 1,344 nucleotides including the stop codon. The deduced primary structure of the protein (447 amino acid residues) strongly resembles that of Gpa1p, the G-protein α subunit from Saccharomyces cerevisiae involved in the mating pheromone response pathway. Nevertheless, unlike disruption ofGpa1 from S. cerevisiae, disruption ofKlGpa1 rendered viable cells with a reduced capacity to mate. Expression of a plasmidic KlGpa1 copy in a ΔKlgpa1 mutant restores full mating competence; hence we conclude that KlGpa1p plays a positive role in the mating pathway. Overexpression of the constitutive subunit KlGpa1p(K364) (GTP bound) does not induce constitutive mating; instead it partially blocks wild-type mating and is unable to reverse the sterile phenotype of ΔKlgpa1 mutant cells. K. lactis expresses a second Gα subunit, KlGpa2p, which is involved in regulating cyclic AMP levels upon glucose stimulation. This subunit does not rescue ΔKlgpa1 cells from sterility; instead, overproduction of KlGpa2p slightly reduces the mating of wild-type cells, suggesting cross talk within the pheromone response pathway mediated by KlGpa1p and glucose metabolism mediated by KlGpa2p. The ΔKlgpa1 ΔKlgpa2 double mutant, although viable, showed the mating deficiency observed in the single ΔKlgpa1 mutant.

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