The function of HHAT (hedgehog acyltransferase, Ensembl gene identifier ENSG00000054392) is as follows. Palmitoyl acyltransferase that catalyzes N-terminal palmitoylation of hedgehog (DHH, IHH or SHH) morphogens, promoting their maturation (PubMed:11486055, PubMed:18534984, PubMed:24784881, PubMed:31875564, PubMed:34112694, PubMed:34890564). Promotes the transfer of palmitoyl-CoA from the cytoplasmic to the luminal side of the endoplasmic reticulum membrane, where hedgehog palmitoylation occurs (PubMed:31875564, PubMed:34112694, PubMed:34890564). Required for hedgehog signaling during limb development (By similarity). Plays a role in proper testis cord formation and the differentiation of Leydig cells (PubMed:24784881). {ECO:0000250|UniProtKB:Q8BMT9, ECO:0000269|PubMed:11486055, ECO:0000269|PubMed:18534984, ECO:0000269|PubMed:24784881, ECO:0000269|PubMed:31875564, ECO:0000269|PubMed:34112694, ECO:0000269|PubMed:34890564}.