K64 acetylation of heat shock protein 90 suppresses nucleopolyhedrovirus replication in Bombyx mori.

HSP90 is a highly conserved chaperone that facilitates the proliferation of many viruses, including silkworm (bombyx mori) nucleopolyhedrovirus (BmNPV), but the underlying regulatory mechanism was unclear. We found that suppression of HSP90 by 17-AAG, a HSP90-specific inhibitor, significantly reduced the expression of BmNPV capsid protein gp64 and viral genome replication, whereas overexpression of B. mori HSP90(BmHSP90) promoted BmNPV replication. Furthermore, in a recent study of the lysine acetylome of B. mori infected with BmNPV, we focused on the reduced viral proliferation due to changes of BmHSP90 lysine acetylation. Site-directed introduction of acetylated (K/Q) or deacetylated (K/R) mimic mutations into BmHSP90 revealed that lysine 64 (K64) acetylation activated the JAK/STAT pathway and reduced BmHSP90 ATPase activity, leading to diminished chaperone activity and ultimately inhibiting BmNPV proliferation. In this study, a single lysine 64 acetylation change of BmHSP90 was elucidated as a model of posttranslational modifications occurring in the wake of host-virus interactions, providing novel insights into potential antiviral strategies.

Functional Diversity of Mammalian Small Heat Shock Proteins: A Review.

The small heat shock proteins (sHSPs), whose molecular weight ranges from 12∼43 kDa, are members of the heat shock protein (HSP) family that are widely found in all organisms. As intracellular stress resistance molecules, sHSPs play an important role in maintaining the homeostasis of the intracellular environment under various stressful conditions. A total of 10 sHSPs have been identified in mammals, sharing conserved α-crystal domains combined with variable N-terminal and C-terminal regions. Unlike large-molecular-weight HSP, sHSPs prevent substrate protein aggregation through an ATP-independent mechanism. In addition to chaperone activity, sHSPs were also shown to suppress apoptosis, ferroptosis, and senescence, promote autophagy, regulate cytoskeletal dynamics, maintain membrane stability, control the direction of cellular differentiation, modulate angiogenesis, and spermatogenesis, as well as attenuate the inflammatory response and reduce oxidative damage. Phosphorylation is the most significant post-translational modification of sHSPs and is usually an indicator of their activation. Furthermore, abnormalities in sHSPs often lead to aggregation of substrate proteins and dysfunction of client proteins, resulting in disease. This paper reviews the various biological functions of sHSPs in mammals, emphasizing the roles of different sHSPs in specific cellular activities. In addition, we discuss the effect of phosphorylation on the function of sHSPs and the association between sHSPs and disease.

A novel submerged Rotala rotundifolia, its growth characteristics and remediation potential for eutrophic waters.

The vegetative growth and remediation potential of Rotala rotundifolia, a novel submerged aquatic plant, for eutrophic waters were investigated on different sediments, and under a range of nitrogen concentrations. Rotala Rotundifolia grew better on silt than on sand and gravel in terms of plant height, tiller number and biomass accumulation. Percent increment of biomass was enhanced at low water nitrogen (ammonium nitrogen concentration ≤10 mg/L). The maximum total nitrogen and total phosphorus removals in the overlying water were between 54% to 66% and 42% to 57%, respectively. Nitrogen contents in the sediments increased with increasing water nitrogen levels, whereas, nitrogen contents in the plant tissues showed no apparent regularity, and the greatest value was obtained at ammonium nitrogen concentration 15 mg/L. Both phosphorus contents in the sediments and tissues of plants were not affected significantly by additional nitrogen supply. Direct nitrogen uptake by plants was in the range of 16% to 39% when total phosphorus concentration was 1.0 mg/L. These results suggested that Rotala Rotundifolia can be used to effectively remove nitrogen and phosphorus in eutrophic waters.