A new 30-kDa ubiquitin-related SUMO-1 hydrolase from bovine brain.
SUMO-1 is a ubiquitin-like protein functioning as an important reversible protein modifier. To date there is no report on a SUMO-1 hydrolase/isopeptidase catalyzing the release of SUMO-1 from its precursor or SUMO-1-ligated proteins in mammalian tissues. Here we found multiple activities that cleave the SUMO-1 moiety from two model substrates, (125)I-SUMO-1-alphaNH-HSTVGSMHISPPEPESEEEEEHYC and/or GST-SUMO-1-(35)S-RanGAP1 conjugate, in bovine brain extracts. Of them, a major SUMO-1 C-terminal hydrolase had been partially purified by successive chromatographic operations. The enzyme had the ability to cleave SUMO-1 not only from its precursor but also from a SUMO-1-ligated RanGAP1 but did not exhibit any significant cleavage of the ubiquitin- and NEDD8-precursor. The activity of SUMO-1 hydrolase was almost completely inhibited by N-ethylmaleimide, but not by phenylmethanesulfonyl fluoride, EDTA, and ubiquitin-aldehyde known as a potent inhibitor of deubiquitinylating enzymes. Intriguingly, the apparent molecular mass of the isolated SUMO-1 hydrolase was approximately 30 kDa, which is significantly smaller than the recently identified yeast Smt3/SUMO-1 specific protease Ulp1. These results indicate that there are multiple SUMO-1 hydrolase/isopeptidases in mammalian cells and that the 30-kDa small SUMO-1 hydrolase plays a central role in processing of the SUMO-1-precursor.
Suzuki
T
T
First Department of Biochemistry, Hamamatsu University School of Medicine, 3600 Handa-cho, Hamamatsu 431-3192, Shizuoka, Japan.
Ichiyama
A
A
Saitoh
H
H
Kawakami
T
T
Omata
M
M
Chung
C H
CH
Kimura
M
M
Shimbara
N
N
Tanaka
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002417:Cattle; D020689:Exopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D025842:SUMO-1 Protein; D013379:Substrate Specificity; D014452:Ubiquitins / Q000378:metabolism*
D020690:GTPase-Activating Proteins; D009419:Nerve Tissue Proteins; D010455:Peptides; D011498:Protein Precursors; D025842:SUMO-1 Protein; D014452:Ubiquitins; D020689:Exopeptidases; C400521:SUMO-1 C-terminal hydrolase