NMR structure of ubiquitin-like domain in PARKIN: gene product of familial Parkinson's disease.
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Amino Acid Sequence↗
Biomedical subjects
Hideyo Yasuda
Publications and source records attributed to Hideyo Yasuda.
Sumoylation of Mdm2 by protein inhibitor of activated STAT (PIAS) and RanBP2 enzymes.
Mdm2, a ubiquitin ligase that acts on p53, is regulated by sumoylation. In the current study, we identify the enzymes responsible for the sumoylation of Mdm2. When mammalian cells are co-transfected with cDNAs encoding Mdm2 and PIAS1 or PIASxbeta (protein inhibitor of activated STAT) as sumoylation enzymes, Mdm2 is highly sumoylated. Mdm2 is also sumoylated in an in vitro system containing PIASxbeta, PIAS1, and RanBP2. When several lysine residues of Mdm2 were sequentially mutated to arginine, the K182R mutant was not sumoylated in intact cells; however, in the in vitro system this mutant was sumoylated by PIAS1, PIASxbeta, and RanBP2 as efficiently as the wild-type Mdm2 protein. Lysine residues 182 and 185 map within the nuclear localization signal of Mdm2. A K185R mutant of Mdm2 is sumoylated in intact cells, whereas a K182R protein is not. Only a Mdm2 protein bearing the K182R mutation is localized exclusively in the cytoplasm. Because RanBP2 is a nuclear pore protein and PIAS proteins are localized within the nucleus, our data suggest that Mdm2 is sumoylated during nuclear translocation by RanBP2 and then further sumoylated once in the nucleus by PIASxbeta and PIAS1.
Active Transport, Cell Nucleus↗
The aryl hydrocarbon receptor nuclear transporter is modulated by the SUMO-1 conjugation system.
The aryl hydrocarbon receptor nuclear transporter (ARNT) is a member of the basic helix-loop-helix/PAS (Per-ARNT-Sim) family of transcription factors, which are important for cell regulation in response to environmental conditions. ARNT is an indispensable partner of the aryl hydrocarbon receptor (AHR) or hypoxia-inducible factor-1alpha. This protein is also able to form homodimers such as ARNT/ARNT. However, the molecular mechanism that regulates the transcriptional activity of ARNT remains to be elucidated. Here, we report that ARNT is modified by SUMO-1 chiefly at Lys(245) within the PAS domain of this protein, both in vivo and in vitro. Substitution of the target lysine with alanine enhanced the transcriptional potential of ARNT per se. Furthermore, green fluorescent protein-fused ARNT tended to form nuclear foci in approximately 20% of the transfected cells, and the foci partly colocalized with PML nuclear bodies. PML, one of the well known substrates for sumoylation, was found to augment the transcriptional activities of ARNT. ARNT bound AHR or PML, whereas the sumoylated form of ARNT associated with AHR, but not with PML, resulting in a reduced effect of PML on transactivation by ARNT. Our data suggest that the sumoylation of ARNT modulates its transcriptional role through affecting the ability of ARNT to interact with cooperative molecules such as PML. This exemplifies a crucial role of protein sumoylation in modulating protein-protein interactions.
Aryl Hydrocarbon Receptor Nuclear Translocator↗
PIAS1 and PIASxalpha function as SUMO-E3 ligases toward androgen receptor and repress androgen receptor-dependent transcription.
The androgen receptor (AR) has been shown to be modified by SUMO-1, a ubiquitin-like protein. Recently we showed that PIAS family proteins function as SUMO-E3 ligases. Here we provide evidence that PIAS1 and PIASxalpha act as specific SUMO-E3 ligases for the AR. PIAS1 and PIASxalpha but not PIAS3 or PIASxbeta enhanced the sumoylation of AR in intact cells and in vitro. PIAS1 and PIASxalpha bound Ubc9, the E2 enzyme for SUMO-1, in a RING finger-like domain-dependent manner. Consistent with previous studies (Kahyo, T., Nishida, T., and Yasuda, H. (2001) Mol. Cell 8, 713-718), the RING finger-like domain of the SUMO-E3 was required for ligase activity. The binding of a ligand, e.g. testosterone, to the AR was required for the sumoylation of AR in intact cells. Although AR-dependent transcription was enhanced by PIAS proteins without sumoylation of the receptor, PIAS1 and PIASxalpha repressed AR-dependent transcription in a manner dependent on the ectopic expression of SUMO-1 and their RING finger-like domain. Furthermore, the sumoylation sites of the AR were necessary for the full repressive effect on AR-dependent transactivation, indicating that the sumoylation of AR was crucial for the repression of transactivation of the AR. Thus, PIAS1 and PIASxalpha modulate the AR-dependent transactivation, which, at least in part, can be attributed to their SUMO-E3 activity toward AR.
Humans↗