22 research outputs found

    BBS proteins interact genetically with the IFT pathway to influence SHH-related phenotypes

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    There are numerous genes for which loss-of-function mutations do not produce apparent phenotypes even though statistically significant quantitative changes to biological pathways are observed. To evaluate the biological meaning of small effects is challenging. Bardetā€“Biedl syndrome (BBS) is a heterogeneous autosomal recessive disorder characterized by obesity, retinopathy, polydactyly, renal malformations, learning disabilities and hypogenitalism, as well as secondary phenotypes including diabetes and hypertension. BBS knockout mice recapitulate most human phenotypes including obesity, retinal degeneration and male infertility. However, BBS knockout mice do not develop polydacyly. Here we showed that the loss of BBS genes in mice result in accumulation of Smoothened and Patched 1 in cilia and have a decreased Shh response. Knockout of Bbs7 combined with a hypomorphic Ift88 allele (orpk as a model for Shh dysfuction) results in embryonic lethality with e12.5 embryos having exencephaly, pericardial edema, cleft palate and abnormal limb development, phenotypes not observed in Bbs7āˆ’/āˆ’ mice. Our results indicate that BBS genes modulate Shh pathway activity and interact genetically with the intraflagellar transport (IFT) pathway to play a role in mammalian development. This study illustrates an effective approach to appreciate the biological significance of a small effect

    A Novel Protein LZTFL1 Regulates Ciliary Trafficking of the BBSome and Smoothened

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    Many signaling proteins including G protein-coupled receptors localize to primary cilia, regulating cellular processes including differentiation, proliferation, organogenesis, and tumorigenesis. Bardet-Biedl Syndrome (BBS) proteins are involved in maintaining ciliary function by mediating protein trafficking to the cilia. However, the mechanisms governing ciliary trafficking by BBS proteins are not well understood. Here, we show that a novel protein, Leucine-zipper transcription factor-like 1 (LZTFL1), interacts with a BBS protein complex known as the BBSome and regulates ciliary trafficking of this complex. We also show that all BBSome subunits and BBS3 (also known as ARL6) are required for BBSome ciliary entry and that reduction of LZTFL1 restores BBSome trafficking to cilia in BBS3 and BBS5 depleted cells. Finally, we found that BBS proteins and LZTFL1 regulate ciliary trafficking of hedgehog signal transducer, Smoothened. Our findings suggest that LZTFL1 is an important regulator of BBSome ciliary trafficking and hedgehog signaling

    Safety out of control: dopamine and defence

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