Recessive TMOD1 mutation causes childhood cardiomyopathy.

Familial cardiomyopathy in pediatric stages is a poorly understood presentation of heart disease in children that is attributed to pathogenic mutations. Through exome sequencing, we report a homozygous variant in tropomodulin 1 (TMOD1; c.565C>T, p.R189W) in three individuals from two unrelated families with childhood-onset dilated and restrictive cardiomyopathy. To decipher the mechanism of pathogenicity of the R189W mutation in TMOD1, we utilized a wide array of methods, including protein analyses, biochemistry and cultured cardiomyocytes. Structural modeling revealed potential defects in the local folding of TMOD1R189W and its affinity for actin. Cardiomyocytes expressing GFP-TMOD1R189W demonstrated longer thin filaments than GFP-TMOD1wt-expressing cells, resulting in compromised filament length regulation. Furthermore, TMOD1R189W showed weakened activity in capping actin filament pointed ends, providing direct evidence for the variant's effect on actin filament length regulation. Our data indicate that the p.R189W variant in TMOD1 has altered biochemical properties and reveals a unique mechanism for childhood-onset cardiomyopathy

Synthesis and in vitro evaluation of the farnesyltransferase inhibitor pepticinnamin E

The farnesyltransferase inhibitor pepticinnamin E was synthesized and shown to have the S configuration at the central, non-proteinogenic amino acid. Using a recombinant yeast farnesyltransferase the biological activity of the natural product and structural analogues was determined. It was shown that pepticinnamin E is a bisubstrate inhibitor. Furthermore, several structural parameters were identified that decisively influence inhibition of the farnesyl transfer

Synthesis and biological evaluation of aeroplysinin analogues: A new class of receptor tyrosine kinase inhibitors

Receptor tyrosine kinases (RTKs), such as the epidermal growth factor receptor (EGFR) and the platelet-derived growth factor receptor (PDGFR), are critically involved in the transduction of mitogenic signals across the plasma membrane and therefore in the regulation of cell growth and proliferation. Enhanced RTK activity is associated with proliferative diseases such as cancer, psoriasis and atherosclerosis, while decreased function may be associated for instance with diabetes. EGFR and PDGFR are selectively inhibited by analogues of the marine natural product aeroplysinin. The synthetic inhibitors display IC50 values in the low micromolar range and in contrast to the natural product show pronounced inhibitory activity in cultured cells in vivo. The mechanism of inhibition is likely based on a covalent modification of the target enzymes by reaction of epoxy ketone 8 with various nucleophiles. (C) 1998 Elsevier Science Ltd. All rights reserved

Copper-Coupled Electron Transfer in Colloidal Plasmonic Copper-Sulfide Nanocrystals Probed by <i>in Situ</i> Spectroelectrochemistry

Copper-sulfide nanocrystals can accommodate considerable densities of delocalized valence-band holes, introducing localized surface plasmon resonances (LSPRs) attractive for infrared plasmonic applications. Chemical control over nanocrystal shape, composition, and charge-carrier densities further broadens their scope of potential properties and applications. Although a great deal of control over LSPRs in these materials has been demonstrated, structural complexities have inhibited detailed descriptions of the microscopic chemical processes that transform them from nearly intrinsic to degenerately doped semiconductors. A comprehensive understanding of these transformations will facilitate use of these materials in emerging technologies. Here, we apply spectroelectrochemical potentiometry as a quantitative <i>in situ</i> probe of copper-sulfide nanocrystal Fermi-level energies (<i>E</i>_F) during redox reactions that switch their LSPR bands on and off. We demonstrate spectroscopically indistinguishable LSPR bands in low-chalcocite copper-sulfide nanocrystals with and without lattice cation vacancies and show that cation vacancies are much more effective than surface anions at stabilizing excess free carriers. The appearance of the LSPR band, the shift in <i>E</i>_F, and the change in crystal structure upon nanocrystal oxidation are all fully reversible upon addition of outer-sphere reductants. These measurements further allow quantitative comparison of the coupled and stepwise oxidation/cation-vacancy-formation reactions associated with LSPRs in copper-sulfide nanocrystals, highlighting fundamental thermodynamic considerations relevant to technologies that rely on reversible or low-driving-force plasmon generation in semiconductor nanostructures