Role of mouse adenovirus type 1 E4orf6-induced degradation of protein kinase R in pathogenesis.

Protein kinase R (PKR) is an interferon-induced antiviral protein activated by autophosphorylation in response to double strand DNA (dsRNA) and other stimuli. Activated PKR causes translation inhibition and apoptosis, and it contributes to proinflammatory responses, cell growth, and differentiation. Mouse adenovirus type 1 (MAV-1) counteracts PKR by causing its degradation via a viral protein, early region 4 open reading frame 6 (E4orf6).

HIV-1 Nef: Taking Control of Protein Trafficking.

The Nef protein of the human immunodeficiency virus is a crucial determinant of viral pathogenesis and disease progression. Nef is abundantly expressed early in infection and is thought to optimize the cellular environment for viral replication. Nef controls expression levels of various cell surface molecules that play important roles in immunity and virus life cycle, by directly interfering with the itinerary of these proteins within the endocytic and late secretory pathways.

Golgi-dependent transport of vacuolar sorting receptors is regulated by COPII, AP1, and AP4 protein complexes in tobacco.

The cycling of vacuolar sorting receptors (VSRs) between early and late secretory pathway compartments is regulated by signals in the cytosolic tail, but the exact pathway is controversial. Here, we show that receptor targeting in tobacco (Nicotiana tabacum) initially involves a canonical coat protein complex II-dependent endoplasmic reticulum-to-Golgi bulk flow route and that VSR-ligand interactions in the cis-Golgi play an important role in vacuolar sorting. We also show that a conserved Glu is required but not sufficient for rate-limiting YXX-mediated receptor trafficking.