p70S6K (RPS6KB1) Protein

p70S6K (RPS6KB1) Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">p70S6K (RPS6KB1)</th>
</tr>
<tr>
<td class="label">Gene</td>
<td>[RPS6KB1](/genes/rps6kb1)</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/Q9UQK2" target="_blank">Q9UQK2</a></td>
</tr>
<tr>
<td class="label">PDB</td>
<td><a href="https://www.rcsb.org/structure/3WE" target="_blank">3WE</a>, <a href="https://www.rcsb.org/structure/4XS0" target="_blank">4XS0</a></td>
</tr>
<tr>
<td class="label">Mol. Weight</td>
<td>~70 kDa</td>
</tr>
<tr>
<td class="label">Localization</td>
<td>Cytoplasm, Nucleus, Synaptic vesicles</td>
</tr>
<tr>
<td class="label">Family</td>
<td>AGC kinase family (PKC/PKB/P70S6K)</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td>[Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), [Diabetes](/diseases/diabetes), [Cancer](/diseases/cancer)</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

p70S6K (RPS6KB1)

Introduction

p70S6K (RPS6KB1) Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">p70S6K (RPS6KB1)</th>
</tr>
<tr>
<td class="label">Gene</td>
<td>[RPS6KB1](/genes/rps6kb1)</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/Q9UQK2" target="_blank">Q9UQK2</a></td>
</tr>
<tr>
<td class="label">PDB</td>
<td><a href="https://www.rcsb.org/structure/3WE" target="_blank">3WE</a>, <a href="https://www.rcsb.org/structure/4XS0" target="_blank">4XS0</a></td>
</tr>
<tr>
<td class="label">Mol. Weight</td>
<td>~70 kDa</td>
</tr>
<tr>
<td class="label">Localization</td>
<td>Cytoplasm, Nucleus, Synaptic vesicles</td>
</tr>
<tr>
<td class="label">Family</td>
<td>AGC kinase family (PKC/PKB/P70S6K)</td>
</tr>
<tr>
<td class="label">Diseases</td>
<td>[Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), [Diabetes](/diseases/diabetes), [Cancer](/diseases/cancer)</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

p70S6K (RPS6KB1)

Introduction

p70S6K (ribosomal protein S6 kinase beta-1), also known as RPS6KB1 or S6K1, is a serine/threonine protein kinase that plays central roles in regulating protein synthesis, cell growth, and metabolic processes. It is a key downstream effector of the [mTOR](/mechanisms/mtor-signaling-pathway) (mechanistic target of rapamycin) signaling pathway and has been implicated in various neurodegenerative diseases including Alzheimer's disease and Parkinson's disease[@burnett1998].

Overview

p70S6K (RPS6KB1) is a member of the AGC (PKA/PKB/PKC) family of serine/threonine kinases. It exists as two isoforms (p70S6Kα1 and p70S6Kα2) generated by alternative splicing. p70S6K is activated by growth factors, nutrients, and cellular energy status through the mTORC1 pathway. Once activated, it phosphorylates numerous substrates to regulate translation, transcription, cell cycle progression, and metabolic processes[@fingar2004].

Structure

p70S6K is a serine/threonine kinase with a complex domain architecture:

Domain Architecture

Isoforms

p70S6K has two isoforms:

• p70S6Kα1 (70 kDa): Full-length isoform with nuclear localization signal
• p70S6Kα2 (70 kDa): Lacks the N-terminal nuclear localization signal

Activation Mechanism

p70S6K activation requires:

• Phosphorylation at multiple sites by mTORC1
• Phosphorylation by PDK1 at the activation loop
• Relief of autoinhibition through conformational changes
• Dimerization of the kinase[@saitoh2002]

Function and Mechanism

Protein Synthesis

p70S6K is a key regulator of translation:

• Phosphorylates ribosomal protein S6, enhancing translation of 5'TOP mRNAs
• Phosphorylates eIF4B, promoting translation initiation
• Phosphorylates eIF4G, facilitating ribosome recruitment
• Regulates translation of specific mRNA subsets involved in cell growth

mTORC1 Signaling

p70S6K is the primary effector of mTORC1:

• Lies directly downstream of mTORC1 in the signaling cascade
• Mediates many of the growth-promoting effects of mTORC1
• Provides feedback regulation of PI3K/Akt signaling
• Integrates nutrient, growth factor, and energy signals

Synaptic Function

In [neurons](/entities/neurons), p70S6K:

• Regulates synaptic plasticity including [LTP](/mechanisms/long-term-potentiation)mechanisms/long-term-potentiation) and LTD
• Modulates dendritic spine morphology
• Controls translation of synaptic proteins
• Participates in learning and memory processes

Metabolic Regulation

p70S6K influences cellular metabolism:

• Regulates glucose uptake and metabolism
• Controls lipid synthesis through SREBP activation
• Modulates insulin signaling
• Affects cell size and growth[@ma2005]

Role in Neurodegenerative Diseases

Alzheimer's Disease

p70S6K is centrally implicated in AD:

Parkinson's Disease

In PD, p70S6K:

• Modulates dopaminergic neuron survival
• Affects [α-synuclein](/proteins/alpha-synuclein) toxicity and aggregation
• Regulates [autophagy](/entities/autophagy), an important clearance pathway
• May contribute to mitochondrial dysfunction

Therapeutic Implications

p70S6K is a therapeutic target:

• mTORC1 inhibitors (rapamycin, everolimus) reduce p70S6K activation
• Modulation may improve synaptic function in neurodegeneration
• p70S6K inhibitors in development for various applications
• Rapamycin being investigated for AD and PD treatment[@cai2010]

Key Publications

See Also

• [mTOR](/mechanisms/mtor-signaling-pathway)

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
• [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)

References