Advances and prospects in targeted protein degradation / 药学实践杂志

Targeted protein degradation (TPD) techniques eliminate pathogenic proteins by hijacking the intracellular proteolysis machinery which includes the ubiquitin-proteasome system (UPS) and the lysosomal degradation pathway, holding promise to overcome the limitations of traditional inhibitors and further broaden the target space including many “undruggable” targets, and provide new targeted treatments for drug discovery. In this review, recent advances in a variety of promising TPD strategies were summarized, such as proteolysis targeting chimera (PROTAC), molecular glue, lysosome-targeting chimaera (LYTAC), autophagosome-tethering compound (ATTEC), autophagy-targeting chimera AUTAC and AUTOTAC, particularly. The representative case studies, potential applications and challenges were analyzed.

Advances of targeted protein degradation technology and its applications in diseases therapy / 生物工程学报

Targeted protein degradation (TPD) technology facilitates specific and efficient degradation of disease-related proteins through hijacking the two major protein degradation systems in mammalian cells: ubiquitin-proteasome system and lysosome pathway. Compared with traditional small molecule-inhibitors, TPD-based drugs exhibit the characteristics of a broader target spectrum. Compared with techniques interfere with protein expression on the gene and mRNA level, TPD-based drugs are target-specific, efficaciously rapid, and not constrained by post-translational modification of proteins. In the past 20 years, various TPD-based technologies have been developed. Most excitingly, two TPD-based therapeutic drugs have been approved by FDA for phase Ⅰ clinical trials in 2019. Despite of the early stage characteristics and various obstructions of the TPD technology, it could serve as a powerful tool for the development of novel drugs. This review summarizes the advances of different degradation systems based on TPD technologies and their applications in disease therapy. Moreover, the advantages and challenges of various technologies were discussed systematically, with the aim to provide theoretical guidance for further application of TPD technologies in scientific research and drug development.

Effects of WNK3 kinase on regulation of large-conductance calcium-activated potassium channels and its mechanisms / 中华肾脏病杂志

Objective To investigate the effects of WNK3 kinase on the regulation of large-conductance calcium-activated potassium channels (Maxi K channels) on African green monkey kidney fibroblast-like cells (Cos-7 cells) and its mechanisms.Methods (1) Cos-7 cells were transfected with 0,0.6,1.2,1.8 μg WNK3 plasmid+0.5 μg Maxi K plasmid.The total protein expression of Maxi K channel and the phosphorylation of mitogen-activated protein kinase (MAPK) extracellular regulated kinase-1 and-2 (ERK1/2) were detected by Western blotting.(2) Cos-7 cells were divided into the control group (2.5 μg Maxi K plasmid) and the experimental group (2.5 μg WNK3 plasmid+2.5 μg Maxi K plasmid).Cell surface biotinylation was used to investigate the cell surface protein expression of Maxi K channel in Cos-7 cells.Immunoprecipitation and Western blotting were used to detect the ubiquitination of Maxi K channel protein.(3) WNK3 kinase was knocked down by WNK3 siRNA.The lysosomal degradation pathway was blocked by the proton pump inhibitor (Baf-A1).Cos-7 cells were divided into Maxi K+negative control siRNA group,Maxi K+WNK3 siRNA group and Maxi K+WNK3 siRNA+Baf-A1 group.The protein expression of Maxi K channel protein was detected by Western blotting.Results (1) Compared with those in 0 μg WNK3 plasmid groups,in 0.6,1.2,1.8 μg WNK3 plasmid groups the total protein expression of the Maxi K channel increased and the phosphorylation level of MAPK ERK1/2 reduced on a dose-dependent manner (all P ＜ 0.01).(2)Compared with those in the control group,the total protein expression and cell surface membrane protein expression of the Maxi K channel increased in the experimental group (P ＜ 0.01),while the ubiquitination of the Maxi K channel protein reduced (P ＜ 0.01).(3) Compared with the Maxi K +negative control siRNA group,the expression of Maxi K protein reduced in the Maxi K+WNK3 siRNA group (P ＜ 0.01),but did not change in the Maxi K+WNK3 siRNA + Bar-A1 group (P ＞ 0.05).The expression of Maxi K protein in Maxi K+WNK3 siRNA+Baf-A1 group was higher than that in Maxi K+WNK3 siRNA group (P ＜ 0.01).Conclusions WNK3 kinase inhibits the lysosomal degradation pathway of Maxi K channel protein by reducing the ubiquitination of Maxi K channel,and promotes the expression of Maxi K channel protein in cells and on cell membrane.These effects may be achieved by suppressing MAPK ERK1/2 signal transduction pathway.