PTGER4

Cilia effects upon perturbation of PTGER4

Cilia number / % ciliated:

Decreased

Loss-of-function effect:

Shorter cilia; decreased % ciliated (EP4 depletion, hRPE1, 25173977)

Ciliogenesis screen results (4 screens)

• Kim2016: No effect
• Wheway et al. 2015 (siRNA) [siRNA]: Ciliogenesis Defect (z=-5.71) PMID:26167766
• Breslow et al. 2018 (CRISPR) [CRISPR]: No Significant Effect PMID:29459680
• Roosing et al. 2015 (siRNA) [siRNA]: Hyper-ciliogenesis (robust z=2.18, ciliated=54.3%) PMID:26595381

Subcellular localization

basal body, cilia

References: PMID:42871245, PMID:25173977

Functional category

• Ciliary assembly/disassembly
• Actin & cytoskeleton regulation
• Cell migration & adhesion
• Signaling (Hedgehog, GPCRs, ion channels)
• Cilia length regulation

Function

Also known as EP4. Activates cAMP-mediated signaling cascade. Together with COX- 2, is required for cilia formation and elongation. Increases the intracellular cAMP and activates protein kinase A (PKA) signaling (25173977). We observed that depletion of ABCC4 or EP4 in hRPE1 cells caused a reduction of ciliaformation and elongation when compared with use of the control siRNA (Fig. 7a, b, c). Bothcilia length and percentages of ciliated cells were significantly reduced in ABCC4 or EP4 depleted cells (Fig. 7g. h). Addition of exogenous PGE2 increased both cilia length and percentages of ciliated cells in control cells but not in EP4-depleted cells (Fig. 7a, d, g, h), indicating that EP4 acts downstream of PGE2 signaling during ciliogenesis. EP4 blockade suppresses DHA-induced neuronal cilia elongation (PMID 42871245).