1.Wdsub1 Regulates The Canonical NF-?B Signaling Pathway 2.The Function Research Of SNAP23 Regulating Cilia Assembly

The transcription factor NF-?B is found in most types of mammalian cells.There are five members in the NF-?B family,including p50/p105,p52/p100,p65(also known as RelA),c-Rel and RelB.NF-?B activation is mediated by canonical and non-canonical signaling pathways.The canonical NF-?B pathway could be activated by many stimuli,such as tumor necrosis factor(TNF),interleukin-1?(Il-1?),reactive oxygen species(ROS).In the resting state,NF-?B(p65/p50)is sequestered in cytoplasm by interacting with I?Ba,a NF-?B inhibitor(13)When cells are under the stimulation such as TNFa,TNFa binds to its receptor TNFR and recruit a series of proteins to form the receptor complex,which activate the IKK kinase complex((40)(42)(42)a(14)(40)(42)(42)b(14)(40)(42)(42)g).Then I?Ba is phosphorylated by IKK complex and degraded through ubiquitination pathway.With the degradation of I?Ba,the dimers of NF-?B(p65/p50)in cytoplasm are translocated to the nucleus and initiate transcription of the target genes,ultimately activate the downstream signaling pathways.In contrast to the canonical pathway,the non-canonical pathway depends on IKKa and is independent of I(40)(42)(42)b(14)(40)(42)(42)g.CD40 L,BAFF and LT?R are critical stimulating factors that could activate non-canonical NF-?B signaling pathway.Under the stimulation,IKKa and NIK kinase proteins are recruited and activated by receptor complex,which could lead to the phosphorylation of p100,and p100 is processed into p52.Finally,nuclear translocation of non-canonical NF-?B members(p52/RelB)turns on the transcription of the target genes.Activation of the NF-?B signaling could induce the transcription of various target genes,which encoding many important proteins such as cytokines,adhesion proteins,immune factors and growth factors and so on.NF-?B signaling plays pivotal roles in various cellular processes,including immune response,inflammation,apoptosis and tumor development.In particular,the dysregulation of NF-?B pathway is involved in many tumor development.It is reported that NF-?B signaling is overactive due to mutations or overexpression of the key genes in this pathway.In tumors cells,the excessive activation of NF-?B pathway could regulate tumor cells proliferation,apoptosis,tumor metastasis and angiogenesis,which ultimately promotes the tumor progression.Previous studies have found that NF-?B pathway is regulated by many kinds of posttranslational modification,such as ubiquitination,phosphorylation,methylation and acetylation.However,there are many unknown mechanisms of NF-?B signaling pathway.In our previous study,we screened for the proteins involved in regulation of NF-?B pathway with the siRNAs library,and identified more than 20 candidates.Among these candidate genes,we decided to focus on the possible involvement of E3 ligase WDSUB1 in NF-?B signaling pathway.WDSUB1 belongs to the U-box E3 ubiquitin ligase family,containing SAM domain and WD40 repeats in addition of the U box.Until now,the biological function of WDSUB1 is largely unknown.Here,we found that knockdown of WDSUB1 significantly inhibit the activation of canonical NF-?B signaling pathway.Furthermore,we found that knockdown of WDSUB1 have no obvious effect on the degradation of I?Ba.Compared to control cells,depletion of WDSUB1 could inhibit the nuclear translocation of p65 and the synthesis of NF-?B target gene I?Ba.Taken together,our data demonstrated that E3 ubiquitin ligase WDSUB1 play an important role in the canonical NF-?B signaling pathway.Above all,we found a new positive regulator of the canonical NF-?B pathway,while the definite regulatory mechanism of WDSUB1 and whether it could be used as a therapeutic target in diseases need further exploration.Primary cilia are antenna-like organelles present in most types of mammalian cells,which are responsible for sensing,integrating and transmitting various extracellular signals.The primary cilia play important roles during embryonic development,mainly through regulating virous signaling pathways including Hedgehog,Wnt and PDGF pathway.Defects in ciliary structure or function have been linked to various developmental diseases named as ciliopathies,such as Senio-Loken Syndrome,Nephronophthisis,Joubert Syndrome,Bardet-Biedl Syndrome and Meckel Syndrome.Primary cilia are closely related to the progression of cell cycle.When the cells enter the cell cycle,the centrosomes replicate in the S phase.During the mitosis,microtubules are transmitted from centrosomes and formed as spindles,ensuring the accurate chromosomes separation.In the quiescent cells,the mother centriole forms the basal body,which initiates cilia assembly.The process of ciliogenesis consists of a series of intricate steps.At the early stage of cilia assembly,the mother centriole begin to dock at the apical plasma membrane,serving as the basal body.Then the transition zone is assembled at the distal end of mother centriole,which is contiguous with the axoneme.Finally,the primary cilia are formed following ciliary axoneme extension depending on the IFT complex.Following the identification of ciliary genes related to ciliopathies,much effect has been focused on the new function and regulation of the primary cilia.In vertebrate cells,it has been reported that various positive regulators could participate in ciliogenesis.However,there are only two well-known regulators,CP110 and its chaperone Cep97,negatively regulate ciliary formation.Interestingly,CP110 and Cep97 need to disappear from the mother centriole during the process of ciliogenesis.However,the mechanism by which CP110 and Cep97 disappear from the mother centriole has remained enigmatic.SNAP23 is belong to SNARE protrein family,which often is localized on the cell membrane in the quiescence cells.It is reported that SNAP23 mainly perform its function in the process of vesicle fusion,and whether SNAP23 is involved in ciliogenesis has not been demonstrated.In this study,we have found that the depletion of SNAP23 with si RNA causes the obvious reduction of primary cilia after serum starvation.To investigate how SNAP23 regulates ciliogenesis,we tested the effects of SNAP23 knockdown on the localization of centrosomal proteins that was known to regulate ciliogenesis.Among these proteins tested,SNAP23 depletion only affected the centrosome localization of two key switch molecules CP110 and Cep97.Taken together,our data indicated that SNAP23 could play a key role in ciliogenesis through regulating CP110 and Cep97 disappearance.And we will further investigate how SNAP23 regulates the disappearance of CP110 and Cep97 from the mother centriole.In conclusion,we have uncovered an unexpected function of SNAP23 as a ciliary regulator.And our data demonstrated that SNAP23 control the cilia formation through regulating the disappearance of CP110 and Cep97.Thus,we report a new regulator in ciliogenesis,expand the function cross between vesicle transport and ciliogensis,and improve to fill the molecular network of ciliogenesis.