The DEAD-box helicase DDX4 promotes this process in vivo to sequester RBPs, including in tumors, but it cannot replicate this process in cultured cancer cells. For 10 points each:
[10m] Name this process, which frequently occurs among proteins with low-complexity domains to form P bodies and stress granules.
ANSWER: liquid-liquid phase separation [or liquid-liquid phase segregation or LLPS or liquid-liquid demixing; prompt on biomolecular condensation by asking “what process drives biomolecular condensation?”; prompt on liquid droplet formation]
[10h] Intrinsically disordered combinations of arginine and these two amino acids facilitate phase separation in DDX4, allowing it to form germ granules. Repeats of these amino acids block proteins larger than 30 kilodaltons from diffusing into the nucleus.
ANSWER: phenylalanine AND glycine [accept Phe or F in place of “phenylalanine”; accept Gly or G in place of “glycine”; accept FG repeats; accept FG nucleoporins or FG Nups]
[10e] Adding this post-translational modification to arginine inhibits DDX4’s ability to phase-separate. DNMTs add this often-heterochromatic mark to CpG islands.
ANSWER: methylation
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