Catalyzes the third of the four reactions of the long-chain fatty acids elongation cycle. This endoplasmic reticulum-bound enzymatic process, allows the addition of two carbons to the chain of long- and very long-chain fatty acids/VLCFAs per cycle. This enzyme catalyzes the dehydration of the 3-hydroxyacyl-CoA intermediate into trans-2,3-enoyl-CoA, within each cycle of fatty acid elongation. Thereby, it participates in the production of VLCFAs of different chain lengths that are involved in multiple biological processes as precursors of membrane lipids and lipid mediators. May be involved in Rac1-signaling pathways leading to the modulation of gene expression. Promotes insulin receptor/INSR autophosphorylation and is involved in INSR internalization (PubMed:25687571). a very-long-chain (3R)-3-hydroxyacyl-CoA = a very-long-chain (2E)-enoyl-CoA + H2O (3R)-hydroxyhexadecanoyl-CoA = (2E)-hexadecenoyl-CoA + H2O Lipid metabolism; fatty acid biosynthesis. May interact with enzymes of the ELO family (including ELOVL1); with those enzymes that mediate condensation, the first of the four steps of the reaction cycle responsible for fatty acids elongation, may be part of a larger fatty acids elongase complex (PubMed:18554506). Interacts with RAC1 (PubMed:10747961). Associates with internalized insulin receptor/INSR complexes on Golgi/endosomal membranes; HACD3/PTPLAD1 together with ATIC and PRKAA2/AMPK2 is proposed to be part of a signaling network regulating INSR autophosphorylation and endocytosis (PubMed:25687571). Highly expressed in testis, kidney, brain, liver and weakly in skeletal muscle, spleen and heart. No expression detected in leukocytes. By AKAP12 and histone deacetylase inhibitors such as sodium butyrate. Belongs to the very long-chain fatty acids dehydratase HACD family. Shares some similarity with tyrosine phosphatase proteins but it has probably no phosphatase activity.