9.B.39 The Long Chain Fatty Acid Translocase (lcFAT) Family
The CD36 antigen, also called platelet glycoprotein IV (GPIV) and the PAS-4 protein (PASIV), has been implicated in the uptake of long chain fatty acids in mouse tissues such as heart, skeletal muscle and adipose tissue (Coburn et al., 2000). The mouse protein, of 472 aas, exhibits two hydrophobic segments that may be TMSs, one at its extreme N-terminus, and one at its extreme C-terminus.
Leptin has been shown to increase fatty acid oxidation and intramuscular triacylglycerol hydrolysis. Chronic leptin administration decreases fatty acid uptake and reduces mRNA levels of FAT/CD36 in rat skeletal muscle (Steinberg et al., 2002). The plasma membrane-associated fatty acid binding protein (FABPpm), also implicated in fatty acid transport, was also expressed at reduced levels following leptin treatment. It acts as a fatty acid sink once fatty acids have crossed the plasma membrane.
The reaction believed to be catalyzed by CD36 is:
long chain fatty acid (out) Æ long chain fatty acid (in)