Classically, hypertrophic cardiomyopathy (HCM) has been viewed as a single-gene (monogenic) disease caused by pathogenic variants in sarcomere genes. Pathogenic sarcomere variants are individually rar Show more
Classically, hypertrophic cardiomyopathy (HCM) has been viewed as a single-gene (monogenic) disease caused by pathogenic variants in sarcomere genes. Pathogenic sarcomere variants are individually rare and convey high risk for developing HCM (highly penetrant). Recently, important polygenic contributions have also been characterized. Low penetrance sarcomere variants (LowSVs) at intermediate frequencies and effect sizes have not been systematically investigated. We hypothesize that LowSVs may be common in HCM with substantial influence on disease risk and severity. Among all sarcomere variants observed in the Sarcomeric Human Cardiomyopathy Registry (SHaRe), we identified putative LowSVs defined by (1) population frequency greater than expected for highly penetrant (monogenic) HCM (allele frequency >5×10 Among 6045 patients and 1159 unique variants in sarcomere genes, 12 LowSVs were identified. LowSVs were collectively common in the general population (1:350) and moderately enriched in HCM (aggregate odds ratio, 14.9 [95% CI, 12.5-17.9]). Isolated LowSVs were associated with an older age of HCM diagnosis and fewer adverse events. However, LowSVs in combination with a pathogenic sarcomere variant conferred higher morbidity (eg, composite adverse event hazard ratio, 5.4 [95% CI, 3.0-9.8] versus single pathogenic sarcomere variant, 2.0 [95% CI, 1.8-2.2]; This study establishes a new class of low penetrance sarcomere variants that are relatively common in the population. When penetrant, isolated LowSVs cause mild HCM. In combination with pathogenic sarcomere variants, LowSVs markedly increase disease severity, supporting a clinically significant additive effect. Last, LowSVs also contribute to age-related remodeling even in the absence of overt HCM. Show less
Most potent protein kinase inhibitors act by competing with ATP to block the phosphotransferase activity of their targets. However, emerging evidence demonstrates that ATP-competitive inhibitors can a Show more
Most potent protein kinase inhibitors act by competing with ATP to block the phosphotransferase activity of their targets. However, emerging evidence demonstrates that ATP-competitive inhibitors can affect kinase interactions and functions in ways beyond blocking catalytic activity. Here, we show that stabilizing alternative ATP-binding site conformations of the mitogen-activated protein kinases (MAPKs) p38α and Erk2 with ATP-competitive inhibitors differentially, and in some cases divergently, modulates the abilities of these kinases to interact with upstream activators and deactivating phosphatases. Conformation-selective ligands are also able to modulate Erk2's ability to allosterically activate the MAPK phosphatase DUSP6, highlighting how ATP-competitive ligands can control noncatalytic kinase functions. Overall, these studies underscore the relationship between the ATP-binding and regulatory sites of MAPKs and provide insight into how ATP-competitive ligands can be designed to confer graded control over protein kinase function. Show less