Fig. 1.

Biogenesis of the large (blue) and small (green) ribosomal subunit and the contribution of AAA-ATPases. Rix7, Rea1, and Drg1 are dedicated to the release and recycling of distinct biogenesis factors from different pre-60S particles. Major landmark of pre-60S ribosomes are depicted together with their corresponding bait proteins. These factors, namely Ssf1, Nsa1, Rix1, Arx1, and Lsg1, are only associated during a short time window with pre-60S particles and thus co-purify rather distinct pre-60S ribosomes. Ssf1 and Nsa1 purify nucleolar particles, whereas Rix1 purifies a nucleoplasmic intermediate. Arx1 represents an export-competent particle that carries export factors. Finally, Lsg1 is associated with an almost mature, cytoplasmic 60S particle. The three AAA-ATPases and their potential substrates are indicated.