Identification of a GNB1 gene variant in a child with autosomal dominant mental retardation 42 / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child featuring global developmental delay.@*METHODS@#DNA was extracted from peripheral blood sample taken from the patient and subjected to whole exome sequencing. Suspected variants were verified by Sanger sequencing of his family members.@*RESULTS@#A heterozygous c.239T>C (p.Ile80Thr) variant of the GNB1 gene was detected in the proband, which was a verified to be de novo in origin.@*CONCLUSION@#The heterozygous c.239T>C (p.Ile80Thr) variant of the GNB1 gene probably underlay the disease in this child.

Synergistic induction of cancer cell migration regulated by Gbetagamma and phosphatidylinositol 3-kinase

Phosphatidylinositol 3-kinase (PI3K) is essential for both G protein-coupled receptor (GPCR)- and receptor tyrosine kinase (RTK)-mediated cancer cell migration. Here, we have shown that maximum migration is achieved by full activation of phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) in the presence of Gbetagamma and PI3K signaling pathways. Lysophosphatidic acid (LPA)-induced migration was higher than that of epidermal growth factor (EGF)-induced migration; however, LPA-induced activation of Akt was lower than that stimulated by EGF. LPA-induced migration was partially blocked by either Gbetagamma or RTK inhibitor and completely blocked by both inhibitors. LPA-induced migration was synergistically increased in the presence of EGF and vice versa. In correlation with these results, sphingosine-1-phosphate (S1P)-induced migration was also synergistically induced in the presence of insulin-like growth factor-1 (IGF-1). Finally, silencing of P-Rex1 abolished the synergism in migration as well as in Rac activation. Moreover, synergistic activation of MMP-2 and cancer cell invasion was attenuated by silencing of P-Rex1. Given these results, we suggest that P-Rex1 requires both Gbetagamma and PI3K signaling pathways for synergistic activation of Rac, thereby inducing maximum cancer cell migration and invasion.