# Mechanism of liquid phase homeostasis of prion-like RNA binding proteins

> **NIH NIH R21** · STATE UNIVERSITY OF NEW YORK AT BUFFALO · 2020 · $197,622

## Abstract

Project Summary/Abstract
Age-onset neurodegenerative diseases, hallmarked by liquid-to-solid protein phase transition, represent a major
public health burden and are rapidly growing worldwide. Therefore, understanding the molecular bases by which
soluble protein molecules transform into pathological aggregates is absolutely crucial to ameliorate protein
homeostasis in cells during stress and aging. RNA-binding proteins containing a prion-like domain (termed
hereafter as prion-like RBPs) form reversible liquid condensates by phase separation in a healthy cell, but
undergo aggregation in degenerating cells as in frontotemporal dementia (FTD), multisystem proteinopathy, and
amyotrophic lateral sclerosis (ALS). This raises two critical questions: (a) what is the role of liquid phase
condensation in pathological aggregation of prion-like RBPs, and (b) what is the mechanism of liquid phase
homeostasis of prion-like RBPs? Besides a prion-like domain, many RBPs also contain an arginine-rich low
complexity domain (R-rich LCD), but its role in their phase separation/aggregation behavior is less clear. The
goals of this proposed research are to (a) systematically evaluate the roles of liquid-liquid phase separation in
the co-aggregation of prion-like domain and R-rich LCD, and (b) examine how cellular polyanions promote the
stability of phase separated condensates against protein aggregation, at the single-molecule level. The PI will
test the hypotheses that the R-rich LCDs act as a nucleator for prion-like RBP aggregation within the phase
separated condensate, whereas polyanions, such as RNA and polyphosphate, binding to R-rich LCD critically
regulates this effect. At the molecular level, R-rich LCDs bind to prion-like sequences by multi-pronged cation-π
interactions, whereas polyanion binding is conferred by a combination of long-range electrostatic and short-
range charge regulated attraction. Since the range and strength of electrostatic interactions (~ 1/r; long-range)
are greater than the cation-π interactions (~ 1/r3; short-range), we envision that RNA/polyphosphate will
effectively counteract the “nucleator” function of R-rich LCDs and promote liquid -phase homeostasis of prion-
like RBPs. To test these ideas, an integrated research strategy will be employed that encompasses a powerful
combination of quantitative fluorescence microscopy, single-molecule fluorescence spectroscopy, small-angle
neutron scattering, and polymer physics-based theories. Results of this project are expected to provide a unified
view of the molecular mechanism of liquid-to-solid phase transition of prion-like RBPs and how
RNA/polyphosphate binding regulates this devastating transformation. Our results are expected to be generally
applicable to other disease-linked protein systems, such as tau phase separation in Alzheimer’s disease (AD).
By uncovering how cellular polyanions, such as RNA and polyphosphate, promote liquid phase homeostasis and
counteract aggregation, we envis...

## Key facts

- **NIH application ID:** 9987450
- **Project number:** 5R21AG064258-02
- **Recipient organization:** STATE UNIVERSITY OF NEW YORK AT BUFFALO
- **Principal Investigator:** Priya R. Banerjee
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $197,622
- **Award type:** 5
- **Project period:** 2019-08-01 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9987450

## Citation

> US National Institutes of Health, RePORTER application 9987450, Mechanism of liquid phase homeostasis of prion-like RNA binding proteins (5R21AG064258-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9987450. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*