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FATP1 and FATP4 mediate long‐chain fatty acid‐induced activation of AMP‐activated protein kinase in adipocytes
Author(s) -
Wiczer Brian Michael,
Lobo Sandra,
Bernlohr David A
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.644.1
Subject(s) - protein kinase a , ampk , biochemistry , amp activated protein kinase , chemistry , fatty acid , kinase , vesicle , biology , membrane
Fatty acid transport protein 1 (FATP1) and FATP4 are the two main FATP family members expressed in adipocytes and are integral membrane proteins that exhibit both long‐chain and very long‐chain acyl‐CoA synthetase activity. The ATP‐dependent acyl‐CoA synthetase reaction of the FATPs has been difficult to study due to the inherent instability of purified enzyme in detergent micelles. To circumvent this problem both FATP1 and FATP4 were reconstituted unidirectionally in an inside‐out orientation into small unilamellar vesicles and the catalytic activity assessed. Reconstituted FATP1 and FATP4 exhibited a specific activity 50% that of the protein in detergent micelles and was independent of the lipid vesicle composition. Importantly, the thermostability of reconstituted FATPs was increased 30‐fold compared with that in detergent micelles. This increased stability allowed for the demonstration that AMP is produced as a product of the FATP acyl‐CoA synthetase reaction. Consistent with AMP production, palmitate influx into 3T3‐L1 adipocytes induced AMP‐activated protein kinase (AMPK) activation, acetyl‐CoA carboxylase phosphorylation, and was decreased in cell lines expressing shRNA targeting either FATP1 or FATP4. These results demonstrate that fatty acid influx and storage, mediated by FATP1 or FATP4 catalytic activity, regulate the AMP‐activated protein kinase. Research supported by ADA‐RA‐12.