SUG1, A COMPONENT OF THE 26-S PROTEASOME, IS AN ATPASE STIMULATED BY SPECIFIC RNAS

Citation
Y. Makino et al., SUG1, A COMPONENT OF THE 26-S PROTEASOME, IS AN ATPASE STIMULATED BY SPECIFIC RNAS, The Journal of biological chemistry, 272(37), 1997, pp. 23201-23205
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology
ISSN journal
0021-9258
Volume
272
Issue
37
Year of publication
1997
Pages
23201 - 23205
Database
ISI
SICI code
0021-9258(1997)272:37<23201:SACOT2>2.0.ZU;2-I
Abstract
SUG1 is an integral component of the 26 S proteasome, Belonging to a n ovel putative ATPase family, it shares four conserved motifs character istic of ATP-dependent DNA/RNA helicases, Recombinant rat SUG1 (rSUG1) produced in Escherichia coil was highly purified and characterized in terms of its biochemical properties. The rSUG1 exhibited a Mg2+-depen dent ATPase activity. The K-m for ATP and V-max of rSUG1 were 35 mu M and 7 pmol of ATP/min/mu g of protein, respectively. Both ATPase activ ity to release [P-32]monophosphate and [P-32]ATP-labeling activity wer e coordinately affected by cold ATP severely, GTP and UTP moderately, and CTP little, Interestingly, the rSUG1 ATPase activity was stimulate d by poly(U) and poly(C), but not by poly(A), poly(G), or by any forms of DNAs tested. A UV crosslinking assay also indicated poly(U)- and p oly(C)-stimulated labeling of rSUG1 with [alpha-P-32]ATP. Moreover, th e ATPase activity was facilitated by cellular poly(A)(+) RNA, but not by poly(A)(-) RNA. RNA transcribed in vitro from cDNA encoding a b-Zip protein could stimulate the ATPase activity, This is the first report to demonstrate a specific RNA requirement for ATPase with respect to the proteasomal ATPases. Our present work suggests that SUG1 can speci fically interact with protein-coding RNA (mRNA) and play some roles in mRNA metabolism.