TY - JOUR

T1 - Characterisation of the nascent polypeptide-associated complex in fission yeast.

AU - Andersen, Katrine M

AU - Semple, Colin A

AU - Hartmann-Petersen, Rasmus

N1 - Keywords: Amino Acid Sequence; Canavanine; Cell Division; Drug Resistance, Fungal; Fungal Proteins; Molecular Chaperones; Molecular Sequence Data; Mutation; Phylogeny; Polyribosomes; Protein Binding; Ribosomes; Schizosaccharomyces; Sequence Homology, Amino Acid; Ubiquitin

PY - 2007

Y1 - 2007

N2 - The nascent polypeptide-associated complex (NAC) is an abundant and phylogenetically conserved protein complex. It is composed of two subunits and interacts with nascent polypeptide chains emerging from the ribosome. It has been proposed to protect the nascent chains from premature interaction with other cell proteins, but has also been found to associate with DNA junctions, and to be involved in other processes including transcription regulation and mitochondrial protein import.Here, we characterize NAC in fission yeast. We find that NAC is associated with ribosomes, while a significant fraction remains in a free form. The NAC alpha subunit contains a ubiquitin-associated (UBA) domain, which is found in several proteins involved in the ubiquitin-proteasome pathway for protein degradation. However, NAC does not associate with ubiquitin chains and mutants lacking NAC did not exhibit any obvious defects in protein degradation. Accordingly, we find that the NAC UBA domain belongs to an ancient and distinct subgroup of the UBA family. In contrast to the situation with budding yeast, fission yeast cells devoid of NAC were not temperature sensitive. However, they displayed resistance to the amino acid analogue canavanine, in accordance with the idea that NAC is involved in protein quality control.

AB - The nascent polypeptide-associated complex (NAC) is an abundant and phylogenetically conserved protein complex. It is composed of two subunits and interacts with nascent polypeptide chains emerging from the ribosome. It has been proposed to protect the nascent chains from premature interaction with other cell proteins, but has also been found to associate with DNA junctions, and to be involved in other processes including transcription regulation and mitochondrial protein import.Here, we characterize NAC in fission yeast. We find that NAC is associated with ribosomes, while a significant fraction remains in a free form. The NAC alpha subunit contains a ubiquitin-associated (UBA) domain, which is found in several proteins involved in the ubiquitin-proteasome pathway for protein degradation. However, NAC does not associate with ubiquitin chains and mutants lacking NAC did not exhibit any obvious defects in protein degradation. Accordingly, we find that the NAC UBA domain belongs to an ancient and distinct subgroup of the UBA family. In contrast to the situation with budding yeast, fission yeast cells devoid of NAC were not temperature sensitive. However, they displayed resistance to the amino acid analogue canavanine, in accordance with the idea that NAC is involved in protein quality control.

U2 - 10.1007/s11033-006-9043-5

DO - 10.1007/s11033-006-9043-5

M3 - Journal article

C2 - 17211518

VL - 34

SP - 275

EP - 281

JO - Molecular Biology Reports

JF - Molecular Biology Reports

SN - 0301-4851

IS - 4

ER -