The primary cilium is an antenna-like structure that protrudes from the cell surface of quiescent/differentiated cells and participates in extracellular signal processing [1][2][3] . Here, we report that mice deficient for the lipid 5-phosphatase Inpp5e develop a multiorgan disorder associated with structural defects of the primary cilium. In ciliated mouse embryonic fibroblasts, Inpp5e is concentrated in the axoneme of the primary cilium. Inpp5e inactivation did not impair ciliary assembly but altered the stability of pre-established cilia after serum addition. Blocking phosphoinositide 3-kinase (PI3K) activity or ciliary platelet-derived growth factor receptor a (PDGFRa) restored ciliary stability. In human INPP5E, we identified a mutation affecting INPP5E ciliary localization and cilium stability in a family with MORM syndrome, a condition related to Bardet-Biedl syndrome. Together, our results show that INPP5E plays an essential role in the primary cilium by controlling ciliary growth factor and PI3K signaling and stability, and highlight the consequences of INPP5E dysfunction.Lipid 5-phosphatases selectively remove the phosphate from position D-5 of the inositol ring of phosphoinositides and inositolphosphates 4,5 . To characterize the functions of the 5-phosphatase Inpp5e 6-8 , we generated Inpp5e D/+ mice ( Supplementary Fig. 1a). We obtained no adult Inpp5e D/D mutant mice from intercrosses between Inpp5e D/+ mice. However, at embryonic day 13.5 (E13.5) and E18.5, 16.9% (11/65) and 14.8% (12/81) of embryos were homozygous for the deletion allele, respectively. The mutant mice died soon after birth, indicating that total inactivation of Inpp5e led to embryonic and postnatal death. Analyses confirmed the absence of Inpp5e protein in mutant cells and tissues (Fig. 1a). Inpp5e D/D mice presented with bilateral anophthalmos (100%, n ¼ 43) and postaxial hexadactyly (62.5%, n ¼ 16; Fig. 1b,c). Histological analyses revealed that eye development ceased at the optic vesicle stage, just before the appearance of the optic cup (Fig. 1d). Analysis of kidneys from the mice revealed the presence of multiple cysts (100%, n ¼ 10; Fig. 1e). Of the cysts, 84% expressed AQP2 and 14% expressed AQP1, indicating an origin in cortical collecting and connecting ducts (when AQP2 + ) as well as proximal tubules and the descending limb of the loop of Henle (when AQP1 + ) ( Supplementary Fig. 2). Only 2% of the renal glomeruli were cystic. Inpp5e D/D embryos had skeletal abnormalities such as a bifid sternum (50%, n ¼ 6), delayed ossification of metacarpals and phalanges (100%, n ¼ 5) and cleft palate (75%, n ¼ 4; Fig. 1f-h). We identified cerebral developmental defects, such as anencephaly and exencephaly, in 30% of Inpp5e D/D embryos at E15.5 (n ¼ 30; Fig. 1i,j). We did not detect liver alterations, laterality defects or respiratory cilium defects in mutant animals. The tissue localization of lesions observed in Inpp5e D/D embryos matched the tissue expression of Inpp5e mRNA during mouse embryogenesis ( Supplementary Fig. 3).Becau...

Apolipoprotein L-I is the trypanolytic factor of human serum. Here we show that this protein contains a membrane pore-forming domain functionally similar to that of bacterial colicins, flanked by a membrane-addressing domain. In lipid bilayer membranes, apolipoprotein L-I formed anion channels. In Trypanosoma brucei, apolipoprotein L-I was targeted to the lysosomal membrane and triggered depolarization of this membrane, continuous influx of chloride, and subsequent osmotic swelling of the lysosome until the trypanosome lysed.

Immortal spheroids were generated from fetal mouse intestine using the culture system initially developed to culture organoids from adult intestinal epithelium. Spheroid proportion progressively decreases from fetal to postnatal period, with a corresponding increase in production of organoids. Like organoids, spheroids show Wnt-dependent indefinite self-renewing properties but display a poorly differentiated phenotype reminiscent of incompletely caudalized progenitors. The spheroid transcriptome is strikingly different from that of adult intestinal stem cells, with minimal overlap of Wnt target gene expression. The receptor LGR4, but not LGR5, is essential for their growth. Trop2/Tacstd2 and Cnx43/Gja1, two markers highly enriched in spheroids, are expressed throughout the embryonic-day-14 intestinal epithelium. Comparison of in utero and neonatal lineage tracing using Cnx43-CreER and Lgr5-CreERT2 mice identified spheroid-generating cells as developmental progenitors involved in generation of the prenatal intestinal epithelium. Ex vivo, spheroid cells have the potential to differentiate into organoids, qualifying as a fetal type of intestinal stem cell.