ribosomal S6 kinase 2 (ribosomal protein S6 kinase alpha 3, S6K-alpha 3, RPS6KA3, 90 kDa ribosomal protein S6 kinase 3, p90-RSK 3, RSK-2, pp90RSK2, insulin-stimulated protein kinase 1, ISPK-1)

Function

• serine/threonine kinase
• may play a role in mediating the growth-factor & stress induced activation of the transcription factor CREB
• forms a complex with either ERK1 or ERK2 in quiescent cells, transiently dissociates following mitogenic stimulation
• activated by multiple phosphorylations on Thr & Ser (putative)
• autophosphorylated on Ser-386, as part of the activation process (putative)
• Ser-227 phosphorylation promotes Ser-386 phosphorylation & leads to basal activation
• full activation by growth factors requires additional phosphorylation on Ser-369 (putative)

Cofactor: Mg+2 (putative)

Structure

• belongs to the protein kinase superfamily, AGC Ser/Thr protein kinase family, S6 kinase subfamily
• contains 1 AGC-kinase C-terminal domain
• contains 2 protein kinase domains

Expression

• expressed in many tissues
• highest levels in skeletal muscle

Pathology

• defects in RPS6KA3 are the cause of Coffin-Lowry syndrome

More general terms

• ribosomal protein S6 kinase

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:6197
• OMIM: https://mirror.omim.org/entry/300075
• OMIM: https://mirror.omim.org/entry/303600
• UniProt: http://www.uniprot.org/uniprot/P51812.html