The impact of Grb2 on phase condensation in live cells

Two-dimensional protein condensation phase transitions on the membrane driven by tyrosine phosphorylation have been identified in several receptor signaling systems, including T cell receptor (via LAT)1,2 and EGFR.3 In the cases of both LAT and EGFR, we have found that the receptor scaffold and Grb2 are sufficient to form a membrane surface condensate in reconstituted systems using supported bilayer membranes. Furthermore, phosphorylation at the Y160 residue on Grb2 is sufficient to block this condensation. To follow up on these reconstitution results in live cells, we created a Grb2-knockout jurkat cell line. Results examining the impact of various Grb2 mutations on condensation in the live cell context using this system will be discussed.