Auxin regulates numerous aspects of plant growth and development,featuring polar auxin transport mediated by auxin efflux and influx carriers.AUX1 is the major auxin importer that actively takes up natural and synthet...Auxin regulates numerous aspects of plant growth and development,featuring polar auxin transport mediated by auxin efflux and influx carriers.AUX1 is the major auxin importer that actively takes up natural and synthetic auxins.However,the precise mechanisms underlying AUX1-mediated auxin recognition and transport remain elusive.Here,we present cryoelectron microscopy structures of Arabidopsis thaliana AUX1 in both apo and auxin-bound states,revealing the structural basis for auxin recognition.Structural analyses show that AUX1 assumes the LeuT-like fold in an inward-facing conformation and the auxin analog 2,4-D is recognized by polar residues located in the central cavity of AUX1.Furthermore,we identify a putative cation-binding site that contributes to stabilizing the inward-facing conformation.Interestingly,we reveal that His249 undergoes a substantial conformational shift,and its mutation completely abolishes transport activity,suggesting a crucial role for His249 in AUX1 gating.Collectively,this study provides a structural foundation for a deeper understanding of auxin influx by AUX1-like carriers.展开更多
Primary ciliary dyskinesia(PCD)is a highly heterogeneous recessive inherited disorder.FAP54,the homolog of CFAP54 in Chlamydomonas reinhardtii,was previously demonstrated as the C1d projection of the central microtubu...Primary ciliary dyskinesia(PCD)is a highly heterogeneous recessive inherited disorder.FAP54,the homolog of CFAP54 in Chlamydomonas reinhardtii,was previously demonstrated as the C1d projection of the central microtubule apparatus of flagella.A Cfap54 knockout mouse model was then reported to have PCD-relevant phenotypes.Through whole-exome sequencing,compound heterozygous variants c.2649_2657delinC(p.E883Dfs*47)and c.7312_7313insCGCAGGCTGAATTCTTGG(p.T2438delinsTQAEFLA)in a new suspected PCD-relevant gene,CFAP54,were identified in an individual with PCD.Two missense variants,c.4112A>C(p.E1371A)and c.6559C>T(p.P2187S),in CFAP54 were detected in another unrelated patient.In this study,a minigene assay was conducted on the frameshift mutation showing a reduction in mRNA expression.In addition,a CFAP54 in-frame variant knock-in mouse model was established,which recapitulated the typical symptoms of PCD,including hydrocephalus,infertility,and mucus accumulation in nasal sinuses.Correspondingly,two missense variants were deleterious,with a dramatic reduction in mRNA abundance from bronchial tissue and sperm.The identification of PCD-causing variants of CFAP54 in two unrelated patients with PCD for the first time provides strong supportive evidence that CFAP54 is a new PCD-causing gene.This study further helps expand the disease-associated gene spectrum and improve genetic testing for PCD diagnosis in the future.展开更多
基金funded by the Shandong Provincial Science and Technology Innovation Fund,the Shandong Provincial Natural Science Foundation(grant no.SYS202206 to J.Z.)the National Key R&D Program of China(grant no.2024YFA1306701 to X.W.D.)+3 种基金the Key Program of the National Natural Science Foundation of China(grant no.32230006 to D.W.,grant nos.32271272 and T2221001 to D.J.,grant nos.22193073,22337002,and 92253305 to X.L.)the Taishan Scholars Program of Shandong Province(to C.C.)the Beijing National Laboratory for Molecular Sciences(grant no.BNLMS-CXX-202106 to X.L.)supported by the New Cornerstone Science Foundation through the XPLORERPRIZE.
文摘Auxin regulates numerous aspects of plant growth and development,featuring polar auxin transport mediated by auxin efflux and influx carriers.AUX1 is the major auxin importer that actively takes up natural and synthetic auxins.However,the precise mechanisms underlying AUX1-mediated auxin recognition and transport remain elusive.Here,we present cryoelectron microscopy structures of Arabidopsis thaliana AUX1 in both apo and auxin-bound states,revealing the structural basis for auxin recognition.Structural analyses show that AUX1 assumes the LeuT-like fold in an inward-facing conformation and the auxin analog 2,4-D is recognized by polar residues located in the central cavity of AUX1.Furthermore,we identify a putative cation-binding site that contributes to stabilizing the inward-facing conformation.Interestingly,we reveal that His249 undergoes a substantial conformational shift,and its mutation completely abolishes transport activity,suggesting a crucial role for His249 in AUX1 gating.Collectively,this study provides a structural foundation for a deeper understanding of auxin influx by AUX1-like carriers.
基金supported by the National Key Research and Development Program of China(No.2016YFC0901502 to Kai-Feng Xu,No.2016YFC0905100 to Xue Zhang,No.2017YFC1001201 to Yaping Liu)the National Natural Science Foundation of China(NSFC)(No.81788101 to Xue Zhang,No.31271345 to Yaping Liu)the CAMS Initiative for Medical Sciences(CIFMS)(Nos.2021-1-I2M-018 and 2016-I2M-1-002 to Xue Zhang and Yaping Liu,Nos.2020-I2M-C&T-B-002 and 2018-I2M-1-003 to Xinlun Tian).
文摘Primary ciliary dyskinesia(PCD)is a highly heterogeneous recessive inherited disorder.FAP54,the homolog of CFAP54 in Chlamydomonas reinhardtii,was previously demonstrated as the C1d projection of the central microtubule apparatus of flagella.A Cfap54 knockout mouse model was then reported to have PCD-relevant phenotypes.Through whole-exome sequencing,compound heterozygous variants c.2649_2657delinC(p.E883Dfs*47)and c.7312_7313insCGCAGGCTGAATTCTTGG(p.T2438delinsTQAEFLA)in a new suspected PCD-relevant gene,CFAP54,were identified in an individual with PCD.Two missense variants,c.4112A>C(p.E1371A)and c.6559C>T(p.P2187S),in CFAP54 were detected in another unrelated patient.In this study,a minigene assay was conducted on the frameshift mutation showing a reduction in mRNA expression.In addition,a CFAP54 in-frame variant knock-in mouse model was established,which recapitulated the typical symptoms of PCD,including hydrocephalus,infertility,and mucus accumulation in nasal sinuses.Correspondingly,two missense variants were deleterious,with a dramatic reduction in mRNA abundance from bronchial tissue and sperm.The identification of PCD-causing variants of CFAP54 in two unrelated patients with PCD for the first time provides strong supportive evidence that CFAP54 is a new PCD-causing gene.This study further helps expand the disease-associated gene spectrum and improve genetic testing for PCD diagnosis in the future.
