An adenovirus inhibitor of tumor necrosis factor alpha-induced apoptosis complexes with dynein and a small GTPase.

Adenoviruses (Ad) code for immunoregulatory and cytokine regulatory proteins, one of which is the early region 3, 14.7-kDa protein (Ad E3-14.7K), which has been shown to inhibit tumor necrosis factor alpha-induced apoptosis. In an effort to understand the mechanism of action of Ad E3-14.7K, we previously searched for cell proteins with which it interacted. Three Ad E3-14.7K-interacting proteins (FIP-1, -2, and -3) were isolated. FIP-1 is a small GTPase which was used in this report as bait in the yeast two-hybrid system to find other interacting cell targets. The search resulted in the isolation of a protein, which we called GIP-1 (GTPase-interacting protein) that subsequently was shown to be identical to one of the light-chain components of human dynein (TCTEL1). FIP-1 was able to bind both TCTEL1 and Ad E3-14.7K simultaneously and was necessary to form a complex in which the viral protein was associated with a microtubule-binding motor protein. The functional significance of these interactions is discussed with respect to the steps of the Ad life cycle which are microtubule associated.