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Published on: May 15, 2019
Anti bacterial function of secreted human FABP3
Ambica Baru1, Chandra Devi1, Tapas Mukhopadhyay1
1National Centre for Human Genome Studies and Research, Panjab University, Sector-14, Chandigarh-160014, India.
Abstract:
FABP3 belongs to a large family of cytoplasmic fatty acid binding proteins that are expressed in a tissue-specific manner. It is predominantly expressed in breast, muscle and heart. During our exploratory studies on the role of FABP3 in tumorigenesis and our consequent attempts to study the molecular mechanism responsible for the oncogenic potential of FABP3, we came across an unexpected role of FABP3 as an anti-bacterial protein. Presence of the protein was detected in culture media of cell lines stably over-expressing human FABP3. Conditioned medium from these FABP3 over-expressing cells exerted a distinct anti-bacterial activity against E. coli. Our results indicate that binding of FABP3 to the bacterial cell surface contributes to its anti-bacterial activity. Incubation of E. coli bacterial cells with FABP3 protein led to disruption of the physical integrity of bacterial cell membrane causing leakage of cellular components. Further, in silico analysis predicted strong binding of FABP3 to the antibiotic binding sites on the bacterial ribosome. Interestingly, we found that FABP3 is a naturally occurring secretory protein present in milk in abundance as confirmed by western blot and ELISA. Thus, our experimental data together with in silico analysis suggests that FABP3 is secreted in milk, has an anti-bacterial function, shows activity against E. coli by disrupting bacterial membrane and targeting the ribosome, and may play a protective role against bacterial infection in newborns.
Insights
Fatty acid-binding protein 3 (FABP3) unexpectedly functions as an antibacterial agent. This protein disrupts bacterial cell membranes and targets ribosomes, offering potential protection against infections in newborns.
Area of Science:
- Biochemistry
- Molecular Biology
- Immunology
Background:
- Fatty acid-binding proteins (FABPs) are a family of cytoplasmic proteins involved in lipid metabolism.
- FABP3 is predominantly expressed in breast, muscle, and heart tissues.
- Initial studies focused on FABP3's role in tumorigenesis.
Purpose of the Study:
- To investigate the unexpected antibacterial properties of FABP3.
- To elucidate the molecular mechanisms underlying FABP3's antibacterial activity.
- To determine the presence and function of FABP3 in milk.
Main Methods:
- Overexpression of human FABP3 in cell lines.
- Collection and testing of conditioned cell culture media for antibacterial activity against E. coli.
- Analysis of FABP3's effect on bacterial cell membrane integrity.
- In silico analysis to predict FABP3 binding to bacterial ribosome antibiotic sites.
- Western blot and ELISA to confirm FABP3 presence in milk.
Main Results:
- Conditioned medium from FABP3-overexpressing cells exhibited antibacterial activity against E. coli.
- FABP3 binding to the bacterial cell surface disrupted membrane integrity, causing leakage.
- In silico analysis predicted FABP3 binding to antibiotic sites on the bacterial ribosome.
- FABP3 was confirmed as a naturally occurring secretory protein abundant in milk.
Conclusions:
- FABP3 possesses significant antibacterial properties against E. coli.
- FABP3 exerts its antibacterial effects by damaging the bacterial cell membrane and inhibiting the ribosome.
- FABP3's presence in milk suggests a role in protecting newborns from bacterial infections.
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