TY - JOUR
T1 - Phase-separating pyrenoid proteins form complexes in the dilute phase
AU - He, Guanhua
AU - GrandPre, Trevor
AU - Wilson, Hugh
AU - Zhang, Yaojun
AU - Jonikas, Martin C.
AU - Wingreen, Ned S.
AU - Wang, Quan
N1 - Funding Information:
We thank Cliff Brangwynne, Alexei Korennykh, Ming-Tzo Wei, and members of the Jonikas, Wang, and Wingreen laboratories for insightful discussions. This work was supported by grants from the National Institutes of Health (R01GM140032), the Howard Hughes Medical Institute and Simons Foundation (55108535), the National Science Foundation (MCB-1935444), and the National Science Foundation through the Center for the Physics of Biological Function (PHY-1734030). H.W. and Q.W. acknowledge support from the Lewis-Sigler Fellowship of Princeton University. G.H. was supported by a China Scholarship Council scholarship. T.G. was supported by the Schmidt Science Fellowship. M.C.J. is a Howard Hughes Medical Institute Investigator.
Publisher Copyright:
© 2023, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.
PY - 2023/12
Y1 - 2023/12
N2 - While most studies of biomolecular phase separation have focused on the condensed phase, relatively little is known about the dilute phase. Theory suggests that stable complexes form in the dilute phase of two-component phase-separating systems, impacting phase separation; however, these complexes have not been interrogated experimentally. We show that such complexes indeed exist, using an in vitro reconstitution system of a phase-separated organelle, the algal pyrenoid, consisting of purified proteins Rubisco and EPYC1. Applying fluorescence correlation spectroscopy (FCS) to measure diffusion coefficients, we found that complexes form in the dilute phase with or without condensates present. The majority of these complexes contain exactly one Rubisco molecule. Additionally, we developed a simple analytical model which recapitulates experimental findings and provides molecular insights into the dilute phase organization. Thus, our results demonstrate the existence of protein complexes in the dilute phase, which could play important roles in the stability, dynamics, and regulation of condensates.
AB - While most studies of biomolecular phase separation have focused on the condensed phase, relatively little is known about the dilute phase. Theory suggests that stable complexes form in the dilute phase of two-component phase-separating systems, impacting phase separation; however, these complexes have not been interrogated experimentally. We show that such complexes indeed exist, using an in vitro reconstitution system of a phase-separated organelle, the algal pyrenoid, consisting of purified proteins Rubisco and EPYC1. Applying fluorescence correlation spectroscopy (FCS) to measure diffusion coefficients, we found that complexes form in the dilute phase with or without condensates present. The majority of these complexes contain exactly one Rubisco molecule. Additionally, we developed a simple analytical model which recapitulates experimental findings and provides molecular insights into the dilute phase organization. Thus, our results demonstrate the existence of protein complexes in the dilute phase, which could play important roles in the stability, dynamics, and regulation of condensates.
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U2 - 10.1038/s42003-022-04373-x
DO - 10.1038/s42003-022-04373-x
M3 - Article
C2 - 36611062
AN - SCOPUS:85145843678
SN - 2399-3642
VL - 6
JO - Communications Biology
JF - Communications Biology
IS - 1
M1 - 19
ER -