Abstract
The ubiquitin-proteasome system for protein degradation plays a major role in regulating cell function and many signaling proteins are tightly controlled by this mechanism. Among these, Regulator of G Protein Signaling 2 (RGS2) is a target for rapid proteasomal degradation, however, the specific enzymes involved are not known. Using a genomic siRNA screening approach, we identified a novel E3 ligase complex containing cullin 4B (CUL4B), DNA damage binding protein 1 (DDB1) and F-box protein 44 (FBXO44) that mediates RGS2 protein degradation. While the more typical F-box partners CUL1 and Skp1 can bind FBXO44, that E3 ligase complex does not bind RGS2 and is not involved in RGS2 degradation. These observations define an unexpected DDB1/CUL4B-containing FBXO44 E3 ligase complex. Pharmacological targeting of this mechanism provides a novel therapeutic approach to hypertension, anxiety, and other diseases associated with RGS2 dysregulation.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cullin Proteins / antagonists & inhibitors
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Cullin Proteins / genetics
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Cullin Proteins / metabolism*
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DNA-Binding Proteins / antagonists & inhibitors
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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F-Box Proteins / antagonists & inhibitors
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F-Box Proteins / genetics
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F-Box Proteins / metabolism*
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Gene Expression Regulation
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Gene Library
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HEK293 Cells
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High-Throughput Screening Assays
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Humans
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Immunoprecipitation
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Mice
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Mice, Inbred C57BL
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Myocardium / chemistry
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Myocardium / metabolism
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Proteasome Endopeptidase Complex / metabolism*
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Protein Binding
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Proteolysis
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RGS Proteins / antagonists & inhibitors
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RGS Proteins / genetics
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RGS Proteins / metabolism*
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RNA, Small Interfering / genetics
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RNA, Small Interfering / metabolism
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Signal Transduction
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Ubiquitination
Substances
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CUL4B protein, human
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Cullin Proteins
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DDB1 protein, human
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DNA-Binding Proteins
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F-Box Proteins
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FBXO44 protein, human
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RGS Proteins
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RGS2 protein, human
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RNA, Small Interfering
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Proteasome Endopeptidase Complex