Body cells like muscle and even cells lining blood vessel or white blood cells migrating toward invading microbes exert mechanical forces. They also respond to forces: sometimes adaptively, such as exercise-induced muscular strengthening, but sometimes destructively, as in muscular dystrophies and other degenerative diseases. Our recent research has discovered that filamin A (FLNa), a major actin filament cross-linking and scaffold protein for numerous cellular components, previously shown to mediate force transmission, also contributes to force responsiveness and revealed insights into how it does so by rearrangement of specific binding sites for binding partners involved in diverse cellular functions. A novel method for detecting protein-protein interactions in cross-linked actin filament networks, Fluorescence Loss After photoconversion (FLAC), enabled this progress. We propose: 1) To obtain further insight into this mechanotrandsduction mechanism by imaging binding interactions of individual FLNa molecules under extension and compression; 2) To determine whether chemical modifications of FLNa and its partners affect their interactions under mechanical force; 3) To identify FLNa binding partners that mediate physiological and pathological mechanical responses. 4) To determine whether FLNa-based mechanotransduction quantified by FLAC to measure FLNa binding kinetics to partners accounts for the stability and persistence of diverse functions of white blood cells (migration, phagocytosis, cytokinesis, spreading on substrates of defined stiffness) and whether force presents a cryptic FLNa binding site partially buried in the cell membrane of CXCR4, an important chemokine receptor involved in white cell migration and HIV viral entry; 5) To determine whether mutant FLNa molecules associated with degenerative diseases cause defective mechanotransduction in vitro and promote apoptosis when expressed in live mechanically stressed cells.

Public Health Relevance

This research concerning a cell protein called filamin A that mediates force transmission and force responsiveness of cells may lead to insights and interventions to promote beneficial effects of force on human body functions such as muscle strengthening and blood cell migration and prevent deleterious ones leading to cell degeneration associated with aging and certain genetic diseases.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL019429-40
Application #
8847760
Study Section
Molecular and Cellular Hematology Study Section (MCH)
Program Officer
Harabin, Andrea L
Project Start
1979-06-01
Project End
2016-05-31
Budget Start
2015-06-01
Budget End
2016-05-31
Support Year
40
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
030811269
City
Boston
State
MA
Country
United States
Zip Code
Song, Mia; He, Qianjing; Berk, Benjamin-Andreas et al. (2016) An adventitious interaction of filamin A with RhoGDI2(Tyr153Glu). Biochem Biophys Res Commun 469:659-64
Gómez-Moutón, Concepción; Fischer, Thierry; Peregil, Rosa M et al. (2015) Filamin A interaction with the CXCR4 third intracellular loop regulates endocytosis and signaling of WT and WHIM-like receptors. Blood 125:1116-25
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Zhou, Xiaohui; Massol, Ramiro H; Nakamura, Fumihiko et al. (2014) Remodeling of the intestinal brush border underlies adhesion and virulence of an enteric pathogen. MBio 5:
Nakamura, Fumihiko; Song, Mia; Hartwig, John H et al. (2014) Documentation and localization of force-mediated filamin A domain perturbations in moving cells. Nat Commun 5:4656
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