RESUMO
Protein Kinase Domain Containing, Cytoplasmic (PKDCC) is a protein kinase which has been implicated in longitudinal bone growth through regulation of chondrocytes formation. Nevertheless, the mechanism by which this occurs remains unknown. Here, we identified two new members of the PKDCC family, Pkdcc1 and Pkdcc2 from Xenopus laevis. Interestingly, our knockdown experiments revealed that these two proteins are both involved on blastopore and neural tube closure during gastrula and neurula stages, respectively. In vertebrates, tissue polarity and cell movement observed during gastrulation and neural tube closure are controlled by Wnt/Planar Cell Polarity (PCP) molecular pathway. Our results showed that Pkdcc1 and Pkdcc2 promote the recruitment of Dvl to the plasma membrane. But surprisingly, they revealed different roles in the induction of a luciferase reporter under the control of Atf2 promoter. While Pkdcc1 induces Atf2 expression, Pkdcc2 does not, and furthermore inhibits its normal induction by Wnt11 and Wnt5a. Altogether our data show, for the first time, that members of the PKDCC family are involved in the regulation of JNK dependent Wnt/PCP signaling pathway.
Assuntos
Proteínas Tirosina Quinases/metabolismo , Proteínas de Xenopus/metabolismo , Xenopus laevis/embriologia , Xenopus laevis/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Movimento Celular , Polaridade Celular , Clonagem Molecular/métodos , Proteínas Desgrenhadas , Regulação da Expressão Gênica no Desenvolvimento , Sistema de Sinalização das MAP Quinases , Fosfoproteínas/metabolismo , Proteínas Tirosina Quinases/genética , Via de Sinalização Wnt , Proteínas de Xenopus/genética , Xenopus laevis/genéticaRESUMO
Chaperone-Mediated Autophagy is a selective form of autophagy. Recently, the degradation of a newly identified CMA substrate, the HIF1A transcription factor, was found to be regulated by the ubiquitin ligase STUB1. In this study we show, for the first time, that K63 ubiquitination is necessary for CMA degradation of HIF1A in vitro and in vivo. Additionally, STUB1 mediates K63 linked ubiquitination of HIF1A. Our findings add a new regulatory step and increase the specificity of the molecular mechanism involved in CMA degradation of HIF1A, expanding the role of ubiquitination to yet another biological process, since the same mechanism might be applicable to other CMA substrates.
