As2O3 enhances the anion transport activity of band 3 and the action is related with the C-terminal 16 residues of the protein.
Successful application of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia (APL) has been attracting worldwide interest, but the exact mechanism for the action of As2O3 remains somewhat obscure. In the present work, we show for the first time that As2O3 facilitates the DIDS-sensitive anion transport activity of band 3 protein in red blood cells (RBCs) isolated from normal adults and APL patients. To elucidate the effect of As2O3 on band 3 protein, constructs encoding the full length of the band 3 transmembrane domain (mdb3) and its C-terminal deletion forms were transfected into yeast cells by a yeast display system. The results demonstrate that deletion of the C-terminal 16 residues of mdb3 (mdb3-d16) does not affect anion transport activity of mdb3 or its sensitivity to DIDS, but decreases its sensitivity to As2O3 in the yeast cell. More intriguingly, the forced expression of intact mdb3 by transfection significantly induces cell apoptosis in HeLa cells, to a higher degree than in cells transfected with mdb3-d16 or empty vector. Expression of activated caspase 3 in HeLa cells also indicates that the C-terminal 16 residues are important for mdb3-mediated apoptosis in cells treated with As2O3. Our results provide the first evidence that As2O3 enhances the anion transport activity of band 3 and the action is related with the C-terminal 16 residues of the protein.
Fu
Guo-Hui
GH
Department of Pathophysiology, Rui-Jin Hospital, Shanghai Second Medical University (SSMU), Shanghai 200025, China. fuguhu@263.net
Wang
Yong
Y
Xi
Yu-Hui
YH
Guo
Zhuo-Wei
ZW
Liu
Xiao-Bin
XB
Bai
Shu-Zhi
SZ
Yang
Bao-Feng
BF
Chen
Guo-Qiang
GQ
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000328:Adult; D001457:Anion Exchange Protein 1, Erythrocyte / Q000235:genetics / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology / Q000627:therapeutic use*; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D017353:Gene Deletion; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D015473:Leukemia, Promyelocytic, Acute / Q000097:blood / Q000188:drug therapy*; D008297:Male; D010087:Oxides / Q000494:pharmacology / Q000627:therapeutic use*; D014162:Transfection; D015003:Yeasts / Q000235:genetics
D001457:Anion Exchange Protein 1, Erythrocyte; D000970:Antineoplastic Agents; D001152:Arsenicals; D010087:Oxides; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D000077237:Arsenic Trioxide