Title:In-Silico and In-Vitro Analysis of Human SOS1 Protein Causing Noonan
Syndrome - A Novel Approach to Explore the Molecular Pathways
Volume: 22
Issue: 7
Author(s): Vinoth Sigamani, Sheeja Rajasingh, Narasimman Gurusamy, Arunima Panda and Johnson Rajasingh*
Affiliation:
- Department of Bioscience Research, University of Tennessee Health Science Center, Memphis, Tennessee
Keywords:
Noonan syndrome, SOS1 gene, in-silico analysis, post-translational modification, nonsynonymous SNP, pathogenicvariants.
Abstract: Aims: Perform in-silico analysis of human SOS1 mutations to elucidate their pathogenic
role in Noonan syndrome (NS).
Background: NS is an autosomal dominant genetic disorder caused by single nucleotide mutation
in PTPN11, SOS1, RAF1, and KRAS genes. NS is thought to affect approximately 1 in 1000. NS
patients suffer different pathogenic effects depending on the mutations they carry. Analysis of the
mutations would be a promising predictor in identifying the pathogenic effect of NS.
Methods: We performed computational analysis of the SOS1 gene to identify the pathogenic nonsynonymous
single nucleotide polymorphisms (nsSNPs) th a t cause NS. SOS1 variants were retrieved
from the SNP database (dbSNP) and analyzed by in-silico tools I-Mutant, iPTREESTAB,
and MutPred to elucidate their structural and functional characteristics.
Results: We found that 11 nsSNPs of SOS1 that were linked to NS. 3D modeling of the wild-type
and the 11 nsSNPs of SOS1 showed that SOS1 interacts with cardiac proteins GATA4, TNNT2,
and ACTN2. We also found that GRB2 and HRAS act as intermediate molecules between SOS1
and cardiac proteins. Our in-silico analysis findings were further validated using induced cardiomyocytes
(iCMCs) derived from NS patients carrying SOS1 gene variant c.1654A>G (NSiCMCs) and
compared to control human skin fibroblast-derived iCMCs (C-iCMCs). Our in vitro data confirmed
that the SOS1, GRB2 and HRAS gene expressions as well as the activated ERK protein, were significantly
decreased in NS-iCMCs when compared to C-iCMCs.
Conclusion: This is the first in-silico and in vitro study demonstrating that 11 nsSNPs of SOS1
play deleterious pathogenic roles in causing NS.
