All C. reinhardtii cultures were grown in TAP medium and harvested by centrifugation (7,500 rpm, 15 min) at exponential growth phase. Pellets were then resuspended in 1 mL of 10 mM sodium phosphate buffer pH 6.8 with 1 mM PMSF as proteinase inhibitor (Díaz-Troya et al., 2008) . Resuspended pellets were subjected to probe sonication with 20/40 s on/off duty cycle on ice. The cell debris was separated from the supernatant by micro-centrifugation at 13,000 rpm for 10 min at 4 C °. The soluble fraction was used to measure total protein using the Bradford method (BioRad, Hercules, CA).
For immunoblotting, the total soluble proteins were separated by 12% SDS-PAGE gels and blotted onto nitrocellulose membrane. The membrane was then blocked by 5% (w/v) nonfat milk in TBST (0.1 M Tris, pH 7.4, 0.15 M NaCl, 0.1% Tween 20) and incubated with monoclonal FLAG tag antibody (ThermoFisher Scientific). Commercial goat anti-rabbit IgG antibody (Invitrogen) was used as the secondary antibody. Signals were detected by ECL Western Blotting Substrat (Promega, USA).
For immunoblotting, the total soluble proteins were separated by 12% SDS-PAGE gels and blotted onto nitrocellulose membrane. The membrane was then blocked by 5% (w/v) nonfat milk in TBST (0.1 M Tris, pH 7.4, 0.15 M NaCl, 0.1% Tween 20) and incubated with monoclonal FLAG tag antibody (ThermoFisher Scientific). Commercial goat anti-rabbit IgG antibody (Invitrogen) was used as the secondary antibody. Signals were detected by ECL Western Blotting Substrat (Promega, USA).