The function of PDE6D (phosphodiesterase 6D, Ensembl gene identifier ENSG00000156973) is as follows. Promotes the release of prenylated target proteins from cellular membranes (PubMed:9712853). Modulates the activity of prenylated or palmitoylated Ras family members by regulating their subcellular location (PubMed:22002721, PubMed:23698361). Required for normal ciliary targeting of farnesylated target proteins, such as INPP5E (PubMed:24166846). Required for RAB28 localization to the cone cell outer segments in the retina (By similarity). Modulates the subcellular location of target proteins by acting as a GTP specific dissociation inhibitor (GDI) (By similarity). Increases the affinity of ARL3 for GTP by several orders of magnitude. Stabilizes ARL3-GTP by decreasing the nucleotide dissociation rate (By similarity). {ECO:0000250|UniProtKB:O55057, ECO:0000269|PubMed:10518933, ECO:0000269|PubMed:22002721, ECO:0000269|PubMed:23559067, ECO:0000269|PubMed:23698361, ECO:0000269|PubMed:24166846, ECO:0000269|PubMed:9712853}.