A Novel Zinc Finger Protein Interacts with Receptor-interacting Protein (RIP) and Inhibits Tumor Necrosis Factor (TNF)- and IL1-induced NF-κB Activation

Danying Chen,Xiaoyan Li,Zhonghe Zhai,Hong-Bing Shu

doi:10.1074/jbc.m108675200

Abstract

Receptor-interacting protein (RIP) is a serine/threonine protein kinase that is critically involved in tumor necrosis factor receptor-1 (TNF-R1)-induced NF-kappa B activation. In a yeast two-hybrid screening for potential RIP-interacting proteins, we identified ZIN (zinc finger protein inhibiting NF-kappa B), a novel protein that specifically interacts with RIP. ZIN contains four RING-like zinc finger domains at the middle and a proline-rich domain at the C terminus. Overexpression of ZIN inhibits RIP-, IKK beta-, TNF-, and IL1-induced NF-kappa B activation in a dose-dependent manner in 293 cells. Domain mapping experiments indicate that the RING-like zinc finger domains of ZIN are required for its interaction with RIP and inhibition of RIP-mediated NF-kappa B activation. Overexpression of ZIN also potentiates RIP- and TNF-induced apoptosis. Moreover, immunofluorescent staining indicates that ZIN is a cytoplasmic protein and that it colocalizes with RIP. Our findings suggest that ZIN is an inhibitor of TNF- and IL1-induced NF-kappa B activation pathways.

Highlights

Receptor-interacting protein (RIP) is a serine/threonine protein kinase that is critically involved in tumor necrosis factor receptor-1 (TNF-R1)-induced NF-␬B activation
Once TRADD is recruited to TNF-R1, it functions as an adapter protein to recruit several structurally and functionally divergent proteins, including FADD, RIP, TRAF2, and cellular inhibitor of apoptosis protein [2, 4]
Studies with RIP- and TRAF2-deficient cells indicate that TRAF2, but not RIP, is required for recruitment of the IKK complex to TNF-R1, whereas RIP is required for activating IKK [25, 26]

Summary

Introduction

Receptor-interacting protein (RIP) is a serine/threonine protein kinase that is critically involved in tumor necrosis factor receptor-1 (TNF-R1)-induced NF-␬B activation. Overexpression of ZIN inhibits RIP-, IKK␤-, TNF-, and IL1-induced NF-␬B activation in a dose-dependent manner in 293 cells. Domain mapping experiments indicate that the RING-like zinc finger domains of ZIN are required for its interaction with RIP and inhibition of RIP-mediated NF-␬B activation. Identification of ZIN—To identify potential RIP-interacting proteins, we used the yeast two-hybrid system to screen a human B cell cDNA library with full-length RIP as bait.

Results

Conclusion