Related Experiment Video
Updated: May 30, 2026
12:11
Simultaneous Affinity Enrichment of Two Post-Translational Modifications for Quantification and Site Localization
Published on: February 27, 2020
Ras, an actor on many stages: posttranslational modifications, localization, and site-specified events
Imanol Arozarena1, Fernando Calvo, Piero Crespo
1Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-IDICAN-Universidad de Cantabria, Departamento de Biología Molecular, Facultad de Medicina, Cantabria, Spain.
Genes & Cancer
|July 23, 2011
Summary
Ras proteins, including H-Ras, K-Ras, and N-Ras, are not confined to the plasma membrane but traffic dynamically between cellular compartments. Their location and post-translational modifications dictate distinct signaling outputs, enabling diverse biological roles.
Area of Science:
- Molecular Biology
- Cell Signaling
- Cellular Compartmentalization
Background:
- Historically, Ras proteins were believed to function solely at the plasma membrane.
- Recent research reveals Ras isoforms (H-Ras, K-Ras, N-Ras) reside in distinct plasma membrane microdomains and are active in endomembranes.
Purpose of the Study:
- To explore the revolutionary concept of spatial regulation in Ras signaling.
- To understand how subcellular localization and dynamic trafficking influence Ras protein function and biological outcomes.
Main Methods:
- The abstract does not specify methods, focusing on conceptual synthesis and established knowledge.
- Relies on existing literature regarding Ras protein localization, post-translational modifications, and effector pathway engagement.
Main Results:
- Ras isoforms exhibit differential localization within the plasma membrane and endomembranes.
- Ras proteins dynamically traffic between cellular compartments.
- Site-specific regulatory mechanisms, including post-translational modifications (phosphorylation, ubiquitination), control Ras activity and effector engagement at distinct locations.
Conclusions:
- Ras signaling is not a singular entity but an integration of site-specific sub-signals.
- Spatial context and regulatory mechanisms confer enormous signal variability, enabling Ras's diverse biological roles.
- Ras serves as a paradigm for how subcellular space differentially shapes cellular signaling pathways.
Related Concept Videos
01:29Translational Regulation
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
01:23Regulation of Expression at Multiple Steps
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the addition of a...
01:27Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...