The potential role of liquid-liquid phase separation in the cellular fate of the compartments for unconventional protein secretion

Author(s)

Mendes, Luis Felipe S. ; Gimenes, Carolina O. ; da Silva, Marilia D. O. ; Rout, Saroj K. ; Riek, Roland ; Costa-Filho, Antonio J.

• Document type: Journal article
• Source: Protein Science; v. 33, n. 7, p. 16-pg., 2024-07-01.

Abstract

Eukaryotic cells have developed intricate mechanisms for biomolecule transport, particularly in stressful conditions. This interdisciplinary study delves into unconventional protein secretion (UPS) pathways activated during starvation, facilitating the export of proteins bypassing most of the components of the classical secretory machinery. Specifically, we focus on the underexplored mechanisms of the GRASP's role in UPS, particularly in biogenesis and cargo recruitment for the vesicular-like compartment for UPS. Our results show that liquid-liquid phase separation (LLPS) plays a key role in the coacervation of Grh1, the GRASP yeast homologue, under starvation-like conditions. This association seems a precursor to the Compartment for Unconventional Protein Secretion (CUPS) biogenesis. Grh1's self-association is regulated by electrostatic, hydrophobic, and hydrogen-bonding interactions. Importantly, our study demonstrates that phase-separated states of Grh1 can recruit UPS cargo under starvation-like situations. Additionally, we explore how the coacervate liquid-to-solid transition could impact cells' ability to return to normal post-stress states. Our findings offer insights into intracellular protein dynamics and cell adaptive responses to stress. (AU)

• FAPESP's process: 22/06006-0 - Elucidating the impact of functional protein liquid and solid condensates in the secretory pathway
• Grantee: Luis Felipe Santos Mendes
• Support Opportunities: Generation Project Research Grant
• FAPESP's process: 15/50366-7 - Resolving mechanistic details of peptide transport across membranes using crystallographic and non-crystallographic structural biology approaches
• Grantee: Antonio José da Costa Filho
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/54044-3 - Acquisition of a fluorescence correlation spectroscope for the measurement of fluorescence correlation and image capture by fluorescence lifetime
• Grantee: Amando Siuiti Ito
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 21/10465-7 - Exploring the dynamic assembly/disassembly of a Golgi matrix protein under stress-conditions
• Grantee: Luis Felipe Santos Mendes
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 20/15542-7 - Design and characterization of micro-reactors constituted by the protein chlorocatechol 1,2-dioxygenase and low complexity domains
• Grantee: Antonio José da Costa Filho
• Support Opportunities: Regular Research Grants