Multifunctional enzyme involved in fatty acid beta-oxidation. Also binds to RNA and microtubules. Possible role in subcellular mRNA localization and RNA-cytoskeleton interactions. a (3S)-3-hydroxyacyl-CoA = a (2E)-enoyl-CoA + H2O a 4-saturated-(3S)-3-hydroxyacyl-CoA = a (3E)-enoyl-CoA + H2O a (3Z)-enoyl-CoA = a 4-saturated (2E)-enoyl-CoA a (3E)-enoyl-CoA = a 4-saturated (2E)-enoyl-CoA (3S)-3-hydroxybutanoyl-CoA = (3R)-3-hydroxybutanoyl-CoA a (3S)-3-hydroxyacyl-CoA + NAD(+) = a 3-oxoacyl-CoA + H(+) + NADH Lipid metabolism; fatty acid beta-oxidation. Monomer. The epimerase and isomerase activities are contained in the N-terminal region while the dehydrogenase activity is in the C-terminal region. In the N-terminal section; belongs to the enoyl-CoA hydratase/isomerase family. In the central section; belongs to the 3-hydroxyacyl-CoA dehydrogenase family.