Modulation of Ciliary Phosphoinositide Content Regulates Trafficking and Sonic Hedgehog Signaling Output

SummaryCiliary transport is required for ciliogenesis, signal transduction, and trafficking of receptors to the primary cilium. Mutations in inositol polyphosphate 5-phosphatase E (INPP5E) have been associated with ciliary dysfunction; however, its role in regulating ciliary phosphoinositides is unknown. Here we report that in neural stem cells, phosphatidylinositol 4-phosphate (PI4P) is found in high levels in cilia whereas phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P2) is not detectable. Upon INPP5E inactivation, PI(4,5)P2 accumulates at the ciliary tip whereas PI4P is depleted. This is accompanied by recruitment of the PI(4,5)P2-interacting protein TULP3 to the ciliary membrane, along with Gpr161. This results in an increased production of cAMP and a repression of the Shh transcription gene Gli1. Our results reveal the link between ciliary regulation of phosphoinositides by INPP5E and Shh regulation via ciliary trafficking of TULP3/Gpr161 and also provide mechanistic insight into ciliary alterations found in Joubert and MORM syndromes resulting from INPP5E mutations

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Contribution à l'étude du métabolisme et du rôle des nucléotides cycliques dans la thyroïde

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Effects of adenosine on secretion and the cyclic AMP-adenylate cyclase system in the dog thyroid

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Evidence that cyclic AMP is not the chemical mediator of the metabolic changes accompanying phagocytosis.

Journal Articleinfo:eu-repo/semantics/publishe

Effects of prostaglandin Fα and arachidonic acid on dog thyroid cyclic AMP level and function

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Modulation of thyroglobulin release by dog thyroid slices

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Reduction due to ageing of TSH-stimulated thyroid hormone release in the cream hamster

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Specificity in signaling and modulators: the Homers.

Newsinfo:eu-repo/semantics/publishe

Determination of cyclic 3', 5'-AMP accumulation in resting and stimulated thyroid slices: Heterogeneity of the ATP precursor pool

SCOPUS: ar.jinfo:eu-repo/semantics/publishe