Prediction of Functional Consequences of Missense Mutations in ANO4 Gene

Abstract

The anoctamin (TMEM16) family of transmembrane protein consists of ten members in vertebrates, which act as Ca2+-dependent ion channels and/or Ca2+-dependent scramblases. ANO4 which is primarily expressed in the CNS and certain endocrine glands, has been associated with various neuronal disorders. Therefore, we focused our study on prioritizing missense mutations that are assumed to alter the structure and stability of ANO4 protein. We employed a wide array of evolution and structure based in silico prediction methods to identify potentially deleterious missense mutations in the ANO4 gene. Identified pathogenic mutations were then mapped to the modeled human ANO4 structure and the effects of missense mutations were studied on the atomic level using molecular dynamics simulations. Our data show that the G80A and A500T mutations significantly alter the stability of the mutant proteins, thus providing new perspective on the role of missense mutations in ANO4 gene. Results obtained in this study may help to identify disease associated mutations which affect ANO4 protein structure and function and might facilitate future functional characterization of ANO4.

Missense variants in ANO4 cause sporadic encephalopathic or familial epilepsy with evidence for a dominant-negative effect

“…Finally, the Asn129Lys variant observed in the individual with childhood-onset regression and moderate ID at teenage age is the only variant located in the N-terminal intracellular region within the predicted dimerization domain (PF16178). 67 In further support of this suggested genotype-phenotype correlation, four population variants with deleterious in silico predictions G115A, A535T, Y707C, and A728T, (dbSNP: rs34162417, rs150353677, rs143089752, and rs200450110, respectively) 84 are either rare and located in extracellular loops (A535T, Y707C, A728T) or very frequent (G115A, MAF 0.0476 with 390 homozygotes in gnomAD v2.1.1) and located in the N-terminal intracellular region but, in contrast to the EE-associated Asn129Lys variant, outside the dimerization domain and without introduction of a charged side chain ( Figure 2 A).…”

Influence of Anoctamin-4 and -9 on ADAM10 and ADAM17 Sheddase Function

“…Moreover, a role in the Central Nervous Systemhas been postulated as well as an association with various neuronal disorders [52][53][54][55]. In addition, Single-Nucleotide Polymorphisms in the ANO4 gene are associated with breast cancer [56,57].…”

Polymodal Control of TMEM16x Channels and Scramblases

“…The TMEM16D plasmalemmal scramblase [42,59,60] also operates as a non-selective cation channel [6], and can be localised in intracellular membranes during heterologous expression [36]. TMEM16D is primarily expressed in the brain [61] and in endocrine glands, including the adrenal zona glomerulosa, where it may stimulate aldosterone secretion and, thus, contribute to renal control of mean arterial pressure [62]. TMEM16D has been linked to various neuronal disorders [63], such as schizophrenia [64], Alzheimer's disease [65], and anxiety disorders [66].…”