Cloning of an L-3-hydroxyacyl-CoA dehydrogenase that interacts with the GLUT4 C-terminus

Evidence indicates that the carboxy-terminal cytoplasmic domain of glucose transporter 4 (GLUT4) is important for the regulation of GLUT4 in muscle and adipocytes. We cloned from a human skeletal muscle cDNA library a 34-kDa protein which interacts with GLUT4 C-terminal cytoplasmic domain in a two-hybrid system and also with GLUT4 C-terminus synthetic peptide in an in vitro binding assay. This protein, called YP10, showed a high degree (>90%) of sequence homology with l-3-hydroxyacyl-CoA dehydrogenase (HAD) and had a dehydrogenase activity similar to pig heart HAD, which was inhibited by GLUT4 C-terminus synthetic peptide. An antiserum raised against pig heart HAD also reacted with YP10. Western blot analysis using this antiserum revealed abundant immunoreactivity only in the mitochondria- and plasma membrane-enriched fractions of rat adipocytes. Northern blots revealed that YP10 mRNA is most abundant in skeletal and heart muscle. These findings suggest that YP10, a HAD isoform, interacts with GLUT4 at the plasma membrane and may play a role in cross-talk between glucose transport and fatty acid metabolism.