RPS6KA1 (Ribosomal Protein S6 Kinase A1), also known as p90RSK1 or MAPKAP-K1, is a serine/threonine kinase that serves as a critical effector of the MAPK/ERK signaling pathway. As part of the ribosomal S6 kinase (RSK) family, RPS6KA1 integrates extracellular signals to regulate diverse cellular processes including protein synthesis, gene transcription, cell cycle progression, and neuronal function. Variants and dysregulation of RPS6KA1 have been implicated in Alzheimer's Disease, Parkinson's Disease, and various neurodegenerative conditions[1][2]. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.
| Attribute | Value |
|---|---|
| Gene Symbol | RPS6KA1 |
| Full Name | Ribosomal Protein S6 Kinase A1 |
| Other Names | p90RSK1, MAPKAP-K1, MSK1, RSK1 |
| Chromosomal Location | 1p36.11 |
| Gene ID | 6195 |
| Protein Class | Serine/Threonine Kinase |
| Family | Ribosomal S6 Kinase (RSK) family |
RPS6KA1 belongs to the ribosomal S6 kinase (RSK) family, which consists of four distinct isoforms (RPS6KA1-4) in humans. These kinases are evolutionarily conserved from yeast to mammals, reflecting their fundamental role in cellular signaling. The RSK family is distinct from other MAPK effectors in having two functionally distinct kinase domains:
This unique architecture allows RSKs to function as both kinases and molecular scaffolds, integrating multiple signaling inputs[1:1].
RPS6KA1 is a 735-amino acid protein with the following structural features:
RPS6KA1 activation proceeds through a multi-step process:
| Site | Kinase | Function |
|---|---|---|
| Ser380 | ERK1/2 | Docking/activation |
| Thr573 | ERK1/2 | Catalytic activation |
| Ser221 | Autophosphorylation | N-terminal activation |
| Ser732 | Autophosphorylation | C-terminal activation |
RPS6KA1 is widely expressed across human tissues with particularly high levels in the brain and proliferative tissues:
Within the central nervous system, RPS6KA1 exhibits region-specific expression:
This widespread brain distribution suggests important roles in diverse neuronal functions.
As a key downstream effector of the MAPK pathway, RPS6KA1 mediates numerous cellular responses:
RPS6KA1 phosphorylates numerous transcription factors:
RPS6KA1 plays a critical role in long-term potentiation (LTP) and memory formation. Studies in mice have demonstrated that:
RPS6KA1 mediates neurotrophin signaling to promote neuronal survival:
RPS6KA1 modulates various ion channels:
RPS6KA1 dysregulation is strongly implicated in Alzheimer's Disease pathogenesis:
The MAPK/ERK pathway is hyperactivated in AD brains, leading to elevated RPS6KA1 activity. This contributes to:
RPS6KA1 involvement in Parkinson's Disease includes:
RPS6KA1 plays a dual role in cerebral ischemia:
While not the focus of this wiki, RPS6KA1 dysregulation is observed in various cancers:
RPS6KA1 interacts with numerous proteins across multiple signaling pathways:
| Partner | Interaction Type | Function |
|---|---|---|
| ERK1/2 (MAPK1/3) | Activation | Phosphorylates and activates RPS6KA1 |
| PDK1 (PDPK1) | Activation | Phosphorylates Ser221 |
| MTOR | Cross-talk | Signaling integration |
| PP1 | Dephosphorylation | Inactivation |
| Substrate | Phosphorylation Site | Effect |
|---|---|---|
| c-Fos | Ser32 | Activation |
| CREB | Ser133 | Activation |
| c-Myc | Ser62 | Stabilization |
| NF-κB p65 | Ser536 | Activation |
| Partner | Interaction Type |
|---|---|
| NMDA Receptor | Modulation |
| AMPA Receptor | Trafficking |
| Synapsin | Phosphorylation |
| SynGAP1 | Regulation |
RPS6KA1 represents a potential therapeutic target for neurodegenerative diseases:
Small molecule RPS6KA1 inhibitors have shown promise:
Roux & Blenis, ERK and p38 MAPK-activated protein kinases (2004). 2004. ↩︎ ↩︎ ↩︎
Pei et al. [Altered MAPK signaling in Alzheimer's disease (2003)](https://doi.org/10.1016/S0301-0082(03). 2003. ↩︎ ↩︎
Zhao et al. p90RSK2 is required for hippocampal synaptic plasticity and memory (2004). 2004. ↩︎
Thomas et al. Regulation of neuronal survival through p90RSK (2002). 2002. ↩︎
West et al. ERK/RSK signaling in tau phosphorylation and aggregation (2023). 2023. ↩︎
Kim et al. RSK2 mediates amyloid-beta-induced neurotoxicity (2011). 2011. ↩︎
Choi et al. RSK2 deficiency attenuates tau pathology in Alzheimer's disease models (2017). 2017. ↩︎
Ma et al. ERK1/2-p90RSK signaling promotes amyloid-beta pathology (2018). 2018. ↩︎
Xing et al. RSK2 protects against oxidative stress in dopaminergic cells (2019). 2019. ↩︎
Liu et al. RSK1-mediated phosphorylation of alpha-synuclein in Lewy body disease (2022). 2022. ↩︎
Yang et al. Role of RSK1/2 in cerebral ischemia and neuroprotection (2021). 2021. ↩︎
Xu et al. p90RSK inhibitors as potential therapeutic agents for neurodegenerative diseases (2023). 2023. ↩︎