A novel cytoplasmic GTPase XAB1 interacts with DNA repair protein XPA

Masahiko Nitta, Masafumi Saijo, Naohiko Kodo, Toshiro Matsuda, Yoshimichi Nakatsu, Hiroshi Tamai, Kiyoji Tanaka

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


The xeroderma pigmentosum group A protein (XPA) plays a central role in nucleotide excision repair (NER). To identify proteins that bind to XPA, we screened a HeLa cDNA library using the yeast two-hybrid system. Here we report a novel cytoplasmic GTP-binding protein, designated XPA binding protein 1 (XAB1). The deduced amino acid sequence of XAB1 consisted of 374 residues with a molecular weight of 41 kDa and an isoelectric point of 4.65. Sequence analysis revealed that XAB1 has four sequence motifs G1-G4 of the GTP-binding protein family in the N-terminal half. XAB1 also contains an acidic region in the C-terminal portion. Northern blot analysis showed that XAB1 mRNA is expressed ubiquitously, and immunofluorescence analysis revealed that XAB1 is localized mainly in the cytoplasm. Consistent with the GTP-binding motif, purified recombinant XAB1 protein has intrinsic GTPase activity. Using the yeast two-hybrid system, we elucidated that XAB1 binds to the N-terminal region of XPA. The deletion of five amino acids, residues 30-34 of XPA, required for nuclear localization of XPA abolished the interaction with XAB1. These results suggest that XAB1 is a novel cytoplasmic GTPase involved in nuclear localization of XPA.

Original languageEnglish
Pages (from-to)4212-4218
Number of pages7
JournalNucleic acids research
Issue number21
Publication statusPublished - Nov 1 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Genetics


Dive into the research topics of 'A novel cytoplasmic GTPase XAB1 interacts with DNA repair protein XPA'. Together they form a unique fingerprint.

Cite this