The function of ZDHHC3 (zDHHC palmitoyltransferase 3, ENSG00000163812) is as follows. Golgi-localized palmitoyltransferase that catalyzes the addition of palmitate onto various protein substrates (PubMed:19001095, PubMed:21926431, PubMed:22240897, PubMed:22314500, PubMed:23034182). Has no stringent fatty acid selectivity and in addition to palmitate can also transfer onto target proteins myristate from tetradecanoyl-CoA and stearate from octadecanoyl-CoA (By similarity). Plays an important role in G protein-coupled receptor signaling pathways involving GNAQ and potentially other heterotrimeric G proteins by regulating their dynamic association with the plasma membrane (PubMed:19001095). Palmitoylates ITGA6 and ITGB4, thereby regulating the alpha-6/beta-4 integrin localization, expression and function in cell adhesion to laminin (PubMed:22314500). Plays a role in the TRAIL-activated apoptotic signaling pathway most probably through the palmitoylation and localization to the plasma membrane of TNFRSF10A (PubMed:22240897). In the brain, by palmitoylating the gamma subunit GABRG2 of GABA(A) receptors and regulating their postsynaptic accumulation, plays a role in synaptic GABAergic inhibitory function and GABAergic innervation (By similarity). Palmitoylates the neuronal protein GAP43 which is also involved in the formation of GABAergic synapses (By similarity). Palmitoylates NCDN thereby regulating its association with endosome membranes (By similarity). Probably palmitoylates PRCD and is involved in its proper localization within the photoreceptor (By similarity). Could mediate the palmitoylation of NCAM1 and regulate neurite outgrowth (By similarity). Could palmitoylate DNAJC5 and regulate its localization to Golgi membranes (By similarity). Also constitutively palmitoylates DLG4 (By similarity). May also palmitoylate SNAP25 (By similarity). Could palmitoylate the glutamate receptors GRIA1 and GRIA2 but this has not been confirmed in vivo (By similarity). Could also palmitoylate the D(2) dopamine receptor DRD2 (PubMed:26535572). May also palmitoylate LAMTOR1, promoting its localization to lysosomal membranes (PubMed:35893977). Palmitoylates the Toll-like receptor 9/TLR9 in the Golgi and thereby regulates TLR9 trafficking to endosomes (PubMed:38169466). May palmitoylate CALHM1 and CALHM3 subunits of gustatory voltage-gated ion channels and modulate channel gating and kinetics (By similarity). Catalyzes the palmitoylation of CADM4 at 'Cys-347', ensuring its localization to the plasma membrane (PM) and protein stability (By similarity). The presence of CADM4 at the PM is essential for its function in CNS myelination, particularly through its associations with other cell adhesion molecules (By similarity). {ECO:0000250|UniProtKB:Q8R173, ECO:0000269|PubMed:19001095, ECO:0000269|PubMed:21926431, ECO:0000269|PubMed:22240897, ECO:0000269|PubMed:22314500, ECO:0000269|PubMed:23034182, ECO:0000269|PubMed:26535572, ECO:0000269|PubMed:35893977, ECO:0000269|PubMed:38169466}. May also function as a calcium transporter. .