Gsα deficiency facilitates cardiac remodeling via CREB/ Bmp10-mediated signaling

The stimulatory G-protein alpha subunit (Gsα), a ubiquitously expressed protein, mediates G-protein receptor-stimulated signal transduction. To investigate the functions of Gsα in cardiomyocytes. We developed transverse aortic constriction (TAC)-induced heart failure mouse models and tamoxifen-inducible transgenic mice with cardiac-specific Gsα disruption. We detected alterations in Gsα expression in TAC-induced heart failure mice. Moreover, we examined cardiac function and structure in mice with genetic Gsα deletion and investigated the underlying molecular mechanisms of Gsα function. We found that Gsα expression increased during the compensated cardiac hypertrophy period and decreased during the heart failure period. Moreover, cardiac-specific Gsα disruption deteriorated cardiac function and induced severe cardiac remodeling. Mechanistically, Gsα disruption decreased CREB1 expression and inhibited the Bmp10-mediated signaling pathway. In addition, we found that Gsα regulates Bmp10 expression through the binding of CREB1 to the Bmp10 promoter. Our results suggest that fluctuations in Gsα levels may play a vital role in the development of heart failure and that loss of Gsα function facilitates cardiac remodeling.

Lack of GNAS re-methylation during oogenesis may be a cause of sporadic pseudohypoparathyroidism type Ib (PHP1B)

Context Pseudohypoparathyroidism type Ib (PHP1B) is characterized by hypocalcemia and hyperphosphatemia due to PTH-resistance in the proximal renal tubules. Maternal pathogenic STX16/GNAS variants leading to maternal epigenetic GNAS changes impair expression of the stimulatory G protein alpha-subunit (Gsα) thereby causing autosomal dominant PHP1B (AD-PHP1B). In contrast, genetic defects responsible for sporadic PHP1B (sporPHP1B) remain mostly unknown. Objective Determine whether PHP1B encountered after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) causes GNAS re-methylation defects similar to those in sporPHP1B. Design Retrospective analysis. Results Nine among thirty-six sporPHP1B patients investigated since 2000, all with LOM at the three maternal GNAS DMRs and gain-of-methylation (GOM) at the paternal NESP DMR, had been conceived through IVF or ICSI. Besides abnormal GNAS methylation, IVF/ICSI-PHP1B cases revealed no additional imprinting defects. Three of these PHP1B patients have dizygotic twins and four have IVF/ICSI-conceived siblings, all with normal GNAS methylation; two unaffected younger siblings were conceived naturally. Conclusion Sporadic and IVF/ICSI-conceived PHP1B patients revealed indistinguishable epigenetic changes at all four GNAS DMRs thus suggesting a similar underlying disease mechanism. Given that re-methylation at the three maternal DMRs occurs during oogenesis, male factors are unlikely to cause LOM post-fertilization. Instead, at least some of the sporPHP1B variants could be caused by a defect(s) in an oocyte-expressed gene that is required for fertility and for re-establishing maternal GNAS methylation imprints. It remains uncertain, however, whether lack of GNAS re-methylation alone impairs oocyte maturation because of insufficient Gsα expression, thus necessitating Assisted Reproductive Technology (ART) for conception.

A molecular toolbox for ADP-ribosyl binding proteins

Proteins interacting with ADP-ribosyl groups are often involved in disease-related pathways or in viral infections, which makes them attractive targets for the development of inhibitors. Our goal was to develop a robust and accessible assay technology that is suitable for high-throughput screening and applicable to a wide range of proteins acting as either hydrolysing or non-hydrolysing binders of mono- and poly-ADP-ribosyl groups. As a foundation of our work, we developed a C-terminal protein fusion tag based on a Gi protein alpha subunit peptide (GAP), which allows for site-specific introduction of cysteine-linked mono- and poly-ADP-ribosyl groups as well as chemical ADP-ribosyl analogs. By fusion of the GAP-tag and ADP-ribosyl binders to fluorescent proteins, we were able to generate robust FRET signals and the interaction with 22 previously described ADP-ribosyl-binders was confirmed. To demonstrate the applicability of this binding assay for high-throughput screening, we utilized it to screen for inhibitors of the SARS-CoV-2 nsp3 macrodomain and identified the drug suramin as a moderate yet unspecific inhibitor of this protein. To complement the binding technology, we prepared high-affinity ADP-ribosyl binders fused to a nanoluciferase, which enabled simple blot-based detection of mono- and poly-ADP-ribosylated proteins. These tools can be expressed recombinantly in E. coli using commonly available agents and will help to investigate ADP-ribosylation systems and aid in drug discovery.

A novel GNAS mutation in pseudohypoparathyroidism type 1a in a Chinese man presented with recurrent seizure: a case report

Background Pseudohypoparathyroidism is a rare genetic disease characterized by hypocalcaemia and hyperphosphataemia due to the defect to the guanine nucleotide-binding protein alpha subunit (GNAS) gene. Patients with pseudoparathyroidism type 1a and 1c could manifest Albright’s hereditary osteodystrophy and multiple hormone resistance including gonadotropin and thyroid stimulating hormone. Case presentation Here we report a Chinese man who presented with fatigue, recurrent seizure and Albright’s hereditary osteodystrophy. His genetic study revealed a heterozygote mutation in the GNAS gene [NM_000516.4(GNAS): c2787_2788del (p.Val930AspfsTer12)]. After calcium and calcitriol supplement, his seizures achieved partially remission. Conclusions We report a case of PHP1a or 1c with a novel frameshift mutation in GNAS gene in a patient presenting with AHO, as well as TSH and partial gonadotropin resistance. This mutation in this case has not been reported in literature and adds to the spectrum of genetic mutations related to PHP.

Correction to: Interaction of the heterotrimeric G protein alpha subunit SSG-1 of Sporothrix schenckii with proteins related to stress response and fungal pathogenicity using a yeast two-hybrid assay

Following the publication of this article [1], it was brought to our attention that Fig. 7A lane 2 is identical to Fig. 7B lane 2 and Fig. 7B lane 4 is identical to Fig. 7C lane 4.