Interaction of antiflammin-1 with uteroglobin-binding protein induces phosphorylation of ERK1/2 in NIH 3T3 cells.
Previously, it has been suggested that uteroglobin (UG)-binding protein functions as a putative receptor of UG; however, the specific epitope of UG that interacts with this receptor has not yet been identified. The downstream events of UG-binding protein signaling remain unclear. Here we report that antiflammin-1 (AF-1, a bioactive C-terminal peptide of UG) specifically binds to UG-binding protein and has a cellular signaling consequence. We reduced the level of endogenous UG-binding protein expression in murine fibroblast cell line NIH 3T3 by RNA interference and found that knockdown of UG-binding protein inhibited AF-1-induced extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation. Meanwhile, the interaction between AF-1 and UG-binding protein was confirmed by flow cytometry-based binding assays and co-localization of AF-1 and enhanced green fluorescent protein (EGFP)-tagged UG-binding protein. The present study provides evidence for the first time for AF-1 binding with UG-binding protein, and preliminarily characterized UG-binding protein as a point downstream of AF-1 in mediating ERK phosphorylation.
Li
Chen
C
Department of Physiology, Xiangya School of Medicine, Central South University, 110 Xiang Ya Road, Changsha 410078, PR China.
Han
Jianzhong
J
Li
Lian
L
Yue
Shaojie
S
Li
Jinfeng
J
Feng
Dandan
D
Liu
Huijun
H
Jiang
Dejian
D
Qin
Xiaoqun
X
Luo
Ziqiang
Z
D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D018613:Microscopy, Confocal; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D041681:NIH 3T3 Cells; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D034622:RNA Interference; D014162:Transfection; D014598:Uteroglobin / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*
D002352:Carrier Proteins; D010446:Peptide Fragments; C064645:antiflammin P1; D049452:Green Fluorescent Proteins; D014598:Uteroglobin; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3