A brain specific alternatively spliced isoform of nonmuscle myosin IIA lacks its mechanoenzymatic activities.

Recent genomic studies reported that 90 to 95% of human genes can undergo alternative splicing, by which multiple isoforms of proteins are synthesized. However, the functional consequences of most of the isoforms are largely unknown. Here, we report a novel alternatively spliced isoform of nonmuscle myosin IIA (NM IIA), called NM IIA2, which is generated by the inclusion of 21 amino acids near the actin-binding region (loop 2) of the head domain of heavy chains. Expression of NM IIA2 is found exclusively in the brain tissue, where it reaches a maximum level at 24 h during the circadian rhythm. The actin-dependent Mg2+-ATPase activity and in vitro motility assays reveal that NM IIA2 lacks its motor activities but localizes with actin filaments in cells. Interestingly, NM IIA2 can also make heterofilaments with NM IIA0 (noninserted isoform of NM IIA) and can retard the in vitro motility of NM IIA, when the two are mixed. Altogether, our findings provide the functional importance of a previously unknown alternatively spliced isoform, NM IIA2, and its potential physiological role in regulating NM IIA activity in the brain.

Comparison of potential inhibitors and targeting fat mass and obesity-associated protein causing diabesity through docking and molecular dynamics strategies.

Genome-wide association studies (GWAS) have identified an association between polymorphisms in the FTO gene and obesity. The FTO: rs9939609, an intronic variant, is considered a risk allele for developing diabesity in homozygous and heterozygous forms. This study aimed to investigate the molecular structure of the available inhibitors specific to the FTO mutations along with the rs9939609 variant. We identified the best-suited inhibitor molecules for each mutant type containing the rs9939609 risk allele. Missense mutations unique to obesity and containing the risk allele of rs9939609 were retrieved from dbSNP for this study. Further stability testing for the mutations were carried out using DynaMut and iStable tools. Three mutations (G187A, M223V, and I492V) were highly destabilizing the FTO structure. These three mutants and native FTO were docked with each of the nine-inhibitor molecules collected from literature studies with the help of PyRx and AutoDock. Further structural behavior of the mutants and native FTO were identified with molecular dynamics simulations and MM-PBSA analyses, along with the 19complex inhibitor compound. We found the compound 19complex exhibited better binding interactions and is the top candidate inhibitor for the M223V and I492V mutants. This study provided insights into the structural changes caused due to mutations in FTO, and the binding mechanism of the inhibitor molecules. It could aid in developing antiobesity drugs for treating patients with mutations and risk alleles predisposing to obesity.