A novel adenovirus E1B19K-binding protein B5 inhibits apoptosis induced by Nip3 by forming a heterodimer through the C-terminal hydrophobic region.
The adenovirus E1B19K protein inhibits apoptosis induced by E1A and other divergent signals. The cellular proteins that interact with E1B19K have been analyzed by isolating cDNA clones by the yeast two hybrid system. One of these clones encodes B5 which consists of 219 amino acid residues and contains the putative BH3 and transmembrane regions. B5 binds strongly to Nip3 and itself, weakly to E1B19K, but not to Bcl-2 and localizes in nuclear envelope, endoplasmic reticulum and mitochondria. B5 has sequence homology with Nip3 in the middle and C-terminal regions, but not in the N-terminal region. Unlike other E1B19K binding BH3 proteins so far characterized, B5 does not induce apoptosis, but inhibits apoptosis induced by Nip3. However the deletion mutant B5Delta1-31 lacking the N-terminus does induce apoptosis, although weaker than does Nip3, suggesting that the N-terminal region is masking the apoptosis-inducing capacity of B5.
Ohi
N
N
Department of Biological Science and Technology, Science University of Tokyo, Noda, Japan.
Tokunaga
A
A
Tsunoda
H
H
Nakano
K
K
Haraguchi
K
K
Oda
K
K
Motoyama
N
N
Nakajima
T
T
D048868:Adaptor Proteins, Signal Transducing; D017501:Adenovirus E1B Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001483:Base Sequence; D015153:Blotting, Western; D019556:COS Cells; D002294:Carcinoma, Squamous Cell; D002352:Carrier Proteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics*; D018076:DNA, Complementary; D019281:Dimerization; D005434:Flow Cytometry; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000737:chemistry; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000378:metabolism / Q000821:virology; D025521:Tumor Suppressor Proteins; D014764:Viral Proteins; D015003:Yeasts / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; D017501:Adenovirus E1B Proteins; C090121:BNIP3 protein, human; C116838:BNIP3L protein, human; D002352:Carrier Proteins; D018076:DNA, Complementary; C119959:E1B19K-binding protein B5; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D014764:Viral Proteins