Related Experiment Video
Updated: Jun 5, 2026
Identification of Protein Interacting Partners Using Tandem Affinity Purification
Published on: February 25, 2012
Identification of an FHL1 protein complex containing ACTN1, ACTN4, and PDLIM1 using affinity purifications and
Parveen Sharma1, Thiruchelvi Shathasivam, Vladimir Ignatchenko
1Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
Insights
This study identified 34 high-confidence binding partners of Four and a half LIM domains protein 1 (FHL1), revealing its role in protein complexes crucial for muscle function and disease.
Area of Science:
- Biochemistry and Molecular Biology
- Cellular Biology
- Genetics
Background:
- Four and a half LIM domains protein 1 (FHL1) is a key protein in muscle development and maintenance.
- Mutations in FHL1 cause X-linked myopathies with cardiac complications.
- Understanding FHL1's interactions is crucial for elucidating its functions.
Purpose of the Study:
- To identify proteins that interact with FHL1.
- To understand the molecular mechanisms underlying FHL1-associated myopathies.
- To delineate the functional complexes of FHL1.
Main Methods:
- Tandem affinity purification of FHL1 from HEK-293 cells.
- Liquid chromatography-mass spectrometry (LC-MS) for protein identification.
- Immunoprecipitation and 3D fluorescence microscopy for interaction validation.
Main Results:
- Identified 34 high-confidence FHL1 binding partners.
- Confirmed FHL1 forms complexes with PDLIM1, GSN, and ACTN1.
- Demonstrated FHL1's role in dynamic protein complexes.
Conclusions:
- FHL1 interacts with specific proteins to form functional complexes.
- These interactions are vital for FHL1's role in muscle health.
- Further research into these interactions may reveal therapeutic targets for FHL1 myopathies.
Introduction:
Four and a half LIM domains protein 1 (FHL1) is the most widely expressed member of the FHL family of proteins, consisting of four and a half highly conserved LIM domains. A multifunctional and integral role for FHL1 has been implicated in muscle development, structural maintenance, and signaling. To date, 27 FHL1 mutations have been identified that result in at least six different X-linked myopathies, with patients often presenting with cardiovascular complications. Since proteins assemble into dynamic complexes within the cell, FHL1 likely mediates its biological functions in conjunction with other proteins. Delineation of FHL1 interactions could provide insight into its regulatory functions.
Methods:
We performed tandem affinity purification from human embryonic kidney 293 (HEK-293) cells to purify FHL1 and interacting proteins. To identify the potential interactors of FHL1 we performed a total of 9 different purifications from HEK-293 cells which included 3 experimental replicates for each biological condition: FHL1, tag control (DPYSL3), and negative control (empty vector). Purified samples were analyzed by liquid chromatography mass spectrometry (LC-MS). Potential interactors were then verified by immunoprecipitation from mouse heart ventricles and interactions visualized in adult cardiomyocytes using 3D fluorescence microscopy.
Results:
We identified a total of 310 different proteins from all 9 purifications and by applying stringent filtering criteria we eliminated all proteins found in any of the controls and only allowed those that were detected in two or more bait purification. We identified 34 high confidence potential binding partners of FHL1. We then showed that FHL1 exists as part of a complex that binds with PDLIM1, GSN and ACTN1.
More Related Videos
12:53Identification of Protein Interaction Partners in Mammalian Cells Using SILAC-immunoprecipitation Quantitative Proteomics
Published on: July 6, 2014
05:43A Protein Preparation Method for the High-throughput Identification of Proteins Interacting with a Nuclear Cofactor Using LC-MS/MS Analysis
Published on: January 24, 2017
