# Molecular Mechanism of Protein Targeting by the Signal Recognition Particle

> **NIH NIH R01** · CALIFORNIA INSTITUTE OF TECHNOLOGY · 2020 · $371,258

## Abstract

Project Summary
Proper localization of proteins is crucial for all cells. The signal recognition particle (SRP) and its
receptor (SR) constitute the major cellular machinery that mediates the co-translational targeting
of roughly one third of cellular proteins to the eukaryotic endoplasmic reticulum, or the bacterial
plasma membrane. Although enormous progress has been made in understanding the simplest
SRP in bacteria, eukaryotic SRP is four times larger and contains five additional protein
subunits. Compared to bacterial SRP, our understanding of the more complex mammalian SRP
lags far behind. In this grant cycle, we will establish a rigorous mechanistic framework for the
mammalian SRP pathway and decipher the role of eukaryote-specific components in this
particle. We will interrogate the molecular mechanisms by which the SRP receptor interacts
with and exerts regulatory functions at the membrane in both the bacterial and mammalian SRP
pathways. Understanding the mammalian SRP pathway will likely unravel new layers of
regulation in higher eukaryotic cells. Comparison between the bacterial and mammalian SRP
will reveal general principles that enable the balance between efficiency and accuracy in both
organisms, and shed light on the interplay between protein and RNA during the evolution of
ancient ribonucleoprotein particles. The proposed research is of a most basic nature, and will
contribute profoundly to our general understanding of physiology and pathology of all living cells
at the molecular level.

## Key facts

- **NIH application ID:** 9856441
- **Project number:** 5R01GM078024-13
- **Recipient organization:** CALIFORNIA INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** Shu-ou Shan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $371,258
- **Award type:** 5
- **Project period:** 2007-09-28 → 2020-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9856441

## Citation

> US National Institutes of Health, RePORTER application 9856441, Molecular Mechanism of Protein Targeting by the Signal Recognition Particle (5R01GM078024-13). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/9856441. Licensed CC0.

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