This report is based upon experiments in Drosophila designed to identify genes involved in later stages of cancer development, including cellular acquisition of invasive behavior. The Drosophila gene S6kII was identified in this screen. Dmel\S6kII encodes a serine/threonine kinase that functions as a downstream effector and regulator of the MAP kinase pathway. Multiple genetic reagents including RNAi-targeting constructs, alleles caused by insertional mutagenesis, and a CRISPR/Cas9-mediated knockout mutation have been generated for S6kII.
Dmel\S6kII is orthologous to four genes in human, RPS6KA1, RPS6KA2 RPS6KA3 and RPS6KA6. A UAS construct of the wild-type human Hsap\RPS6KA3 gene has been introduced into flies, but has not been characterized. Using a breast cancer cell line, the effect of knockdown of RPS6KA3 was assessed; a significant increase in both invasion and migration was observed. The other orthologous RPS6KA human genes were not tested in this assay.
[updated Nov. 2020 by FlyBase; FBrf0222196]
RPS6KA3 encodes a member of the RSK (ribosomal S6 kinase) family of serine/threonine kinases. This kinase contains 2 non-identical kinase catalytic domains and phosphorylates various substrates, including members of the mitogen-activated kinase (MAPK) signaling pathway; implicated in controlling cell growth and differentiation. [Gene Cards, RPS6KA3; 2020.11.28]
Many to one: 4 human genes to 1 Drosophila gene.
Moderate- to high-scoring ortholog of human RPS6KA1, RPS6KA2, RPS6KA3, and RPS6KA6 (1 Drosophila to 4 human). Dmel\S6kII shares 56-58% identity and 69-71% similarity with the human genes.