Snapin, Positive Regulator of Stimulation- Induced Ca2+ Release through RyR, Is Necessary for HIV-1 Replication in T Cells

Shigemi M Kinoshita,Amane Kogure,Shizuka Taguchi,Garry P Nolan,Guido Poli

doi:10.1371/journal.pone.0075297

Abstract

To identify critical host factors necessary for human immunodeficiency virus 1 (HIV-1) replication, large libraries of short-peptide-aptamers were expressed retrovirally. The target of one inhibitor peptide, Pep80, identified in this screen was determined to be Snapin, a protein associated with the soluble N-ethyl maleimide sensitive factor adaptor protein receptor (SNARE) complex that is critical for calcium-dependent exocytosis during neurotransmission. Pep80 inhibited Ca2+ release from intracellular stores and blocked downstream signaling by direct interruption of the association between Snapin and an intracellular calcium release channel, the ryanodine receptor (RyR). NFAT signaling was preferentially abolished by Pep80. Expression of Snapin overcame Pep80-mediated inhibition of Ca2+/NFAT signaling and HIV-1 replication. Furthermore, Snapin induced HIV-1 replication in primary CD4+ T cells. Thus, through its interaction with RyR, Snapin is a critical regulator of Ca2+ signaling and T cell activation. Use of the genetically selected intracellular aptamer inhibitors allowed us to define unique mechanisms important to HIV-1 replication and T cell biology.

Highlights

T cell activation is essential for productive human immunodeficiency virus 1 (HIV-1) infection in primary T cells since essential processes or molecules that permit HIV-1 replication become readily available following T cell induction [1,2,3]
These cells are killed by stimuli that activate HIV-1 long terminal repeat (LTR) activity such as phytohaemagglutinin (PHA) or tumor necrosis factor-alpha (TNF-a) [16]
It is likely that critical host factors for HIV-1 replication that are primed during physiological activation of primary T cells are constitutively active in these T cell lines [26]

Summary

Introduction

T cell activation is essential for productive HIV-1 infection in primary T cells since essential processes or molecules that permit HIV-1 replication become readily available following T cell induction [1,2,3]. This activation process is initiated by the interaction of the T cell antigen receptor (TCR) with antigenderived peptide bound to the major histocompatibility complex (MHC) on the antigen presenting cells (APC). The resulting, long-lasting elevation in cytoplasmic Ca2+ concentration activates Ca2+ signaling pathways, including those mediated by calcineurin and NFAT, that control T cell activation and differentiation in the immune response [8]

Methods

Results

Conclusion