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Updated: Jul 19, 2026
11:13
Identification of Kinase-substrate Pairs Using High Throughput Screening
Published on: August 29, 2015
A retrovirus-based protein complementation assay screen reveals functional AKT1-binding partners.
Zhiyong Ding1, Jiyong Liang, Yiling Lu
1Department of Molecular Therapeutics, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Box 950, Houston, TX 77030, USA.
Summary
We developed a retrovirus-based protein-fragment complementation assay (RePCA) to discover protein interactions. This method identified alpha-actinin 4 (ACTN4) as a key regulator of the AKT1 protein kinase signaling pathway.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Protein-protein interactions are crucial for cellular functions.
- Identifying these interactions is key to understanding complex biological pathways.
- Existing methods may have limitations in sensitivity or scope.
Purpose of the Study:
- To develop and validate a novel retrovirus-based protein-fragment complementation assay (RePCA) for identifying protein-protein interactions in mammalian cells.
- To identify novel interaction partners and substrates of the serine/threonine protein kinase AKT1.
- To functionally characterize the interaction between AKT1 and alpha-actinin 4 (ACTN4).
Main Methods:
- Development of RePCA using fluorescent protein fragments fused to bait proteins and endogenous proteins via retroviral vectors.
- Screening for interactions with AKT1 using the RePCA system.
- Confirmation of interactions using co-immunoprecipitation and functional assays.
- siRNA-mediated knockdown of ACTN4 to assess its effect on AKT1 signaling.
Main Results:
- The RePCA system successfully identified 24 potential interaction partners/substrates of AKT1.
- Alpha-actinin 4 (ACTN4) was confirmed as a physical and functional interactor of AKT1.
- ACTN4 silencing led to decreased AKT phosphorylation, inhibited membrane translocation, increased p27(Kip1) levels, and reduced cell proliferation.
Conclusions:
- RePCA is an effective method for discovering protein-protein interactions in mammalian systems.
- ACTN4 plays a critical role in regulating AKT1 localization and function.
- The findings provide new insights into AKT1 signaling pathways and potential therapeutic targets.
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