Mutation in the ATP binding domain of Sam1 inhibits recruitment of Sam1 and Sam2 to SGs. (A) Domain organization of Sam1 protein noting the location of inactivating point mutations. (B) Representative fluorescence images of endogenously expressed WT or mutant Sam1-GFP. (C) Dot plot displaying foci-to-cytoplasm ratios for endogenously expressed WT and mutant alleles of Sam1-GFP. Red lines mark median value. (D) Representative fluorescence images of colocalization endogenously expressed WT or D121N Sam1-GFP with RFP-tagged Sam2, Ade17, Ded1, or Pbp1. (E) Dot plot displaying foci-to-cytoplasm ratios for endogenously expressed RFP-tagged Sam2, Ade17, Ded1, and Pbp1 in both WT and SAM1 D121N backgrounds. Red lines mark median value. Scale bars in B and D are 5 µM. Statistical significance in C and E was determined by one-tailed Welch’s t test (*, P < 0.05).