1. Receptors for prostaglandin D2. The two G-protein-coupled receptors seem to have opposite effects: e.g. neuroprotection by PGD is mediated by DP1 whereas activation of DP2 promotes neuronal loss. DP2 is preferentially expressed on type 2 lymphocytes, eosinophils, and basophils and is thought to be important in the promotion of Th2-related inflammation.
2. Transcription factors (E2F dimerization partners) that form heterodimers with E2F and regulate the cell cycle. DP-1 is highly expressed in the ectoderm and all epidermal layers during embryogenesis; there are additional isoforms, DP-1α, 278 aa; DP-1β, 357 aa. DP2 exists in several alternatively-spliced forms.
3. A pneumococcal bacteriophage (Dp-1) that encodes a lytic enzyme, N-acetylmuramoyl-l-alanine amidase.