9.A.50 The Nuclear t-RNA Exporter (t-Exporter) Family

tRNAs are made in the nucleolus of the nuclei of eukaryotes. They are processed and exported into the cytoplasm. The t-exporter consists of several proteins. The protein t-UTP8 acts between maturation and translocation across the nuclear pore complex. It interacts with the two tRNA export receptors, Los1 and Msn5, and the Ran GTPase, Gsp1 t-UTP8, probably transfers tRNA to the nuclear tRNA export receptors by using a channeling mechanism (Strub et al., 2007).

The transport reaction catalyzes by the t-exporter is:

tRNA (nucleus) → tRNA (cytoplasm)

This family belongs to the .



Strub, B.R., M.B. Eswara, J.B. Pierce, and D. Mangroo. (2007). Utp8p is a nucleolar tRNA-binding protein that forms a complex with components of the nuclear tRNA export machinery in Saccharomyces cerevisiae. Mol. Biol. Cell 18: 3845-3859.


TC#NameOrganismal TypeExample
9.A.50.1.1The tRNA nuclear export machinery, t-Exporter. Includes UTP8, a tRNA-binding protein, Los1 and Msn5/ two tRNA export receptors (Strub et al., 2007)YeasttRNA Exporter of Saccharomyces cerevisiae:
1. t-UTP8 (P53276)
2. Exportin T (Los1; karyopherin-β) (P33418)
3. Msn5 (P52918)
4. GTP-binding nucleolus protein, GSP1/CNR1 (P32835)