Table 1.
Protein Subunits of the Eukaryotic Exosome and Their Archaeal Counterparts
| Eukaryotic subunit (yeast) | Activity | Domain architecture | Archaeal ortholog (non-orthologous homolog) | |||||
| Sso | Ap | Af | Ph/Pa | Mj | Mth | |||
| Core subunits | ||||||||
| Rrp41p/Ski6p | 3′–5′ exonuclease | RNase PH | 6015742 | APE1447 | AF0493 | PH1549/PAB0420 | — | MTH683 |
| Rrp42p | RNase PH | 6015744 | APE1445 | AF0494 | PH1548/PAB0421 | — | MTH682 | |
| Rrp43p | RNase PH | (6015744) | (APE1445) | (AF0494) | (PH1548/PAB0421) | — | (MTH682) | |
| Rrp44p/Dis3p | PIN + RNase II + S1 | — | — | — | — | — | — | |
| Rrp45p | RNase PH | (6015744) | (APE1445) | (AF0494) | (PH1548/PAB0421) | — | (MTH682) | |
| Rrp46p | RNase PH | (6015742) | (APE1447) | (AF0493) | (PH1549/PAB0420) | — | (MTH683) | |
| Mtr3p | RNase PH | (6015742) | (APE1447) | (AF0493) | (PH1549/PAB0420) | — | (MTH683) | |
| Rrp4p | RNA-binding; 3′–5′ exonuclease?? | S1 + KH | 6015740 | APE1448 | AF0492 | PH1551/PAB0419 | — | MTH684 |
| Rrp40p | RNA-binding | S1 + KH | (6015740) | (APE1448) | (AF0492) | (PH1551/PAB0419) | — | (MTH684) |
| Cs14p | RNA-binding | S1 + (Zn-ribbon) | ?? | APE0445 | AF0206 | PH1551/PAB0419 | — | MTH1318 |
| Nuclear subunit | ||||||||
| Rrp6p | 3′–5′ exonuclease | RNase D + HRDC | — | — | — | — | — | — |
| Associated factors | ||||||||
| Mtr4p | RNA helicase | SFII helicase | ?? | (APE0191) | (AF2245) | (PH1280) | (MJ1124) | (MTH810) |
| Ski2p | SFII helicase | ?? | (APE0191) | (AF2245) | (PH1280) | (MJ1124) | (MTH810) | |
| Ski3p | TPR | ? | ? | ? | ? | ? | ? | |
| Ski8p | WD40 | — | — | — | — | — | — | |
