Cov protein DELLA raug khaws ciacov tshuaj tswj kev loj hlobuas ua lub luag haujlwm tseem ceeb hauv kev loj hlob ntawm cov nroj tsuag los teb rau cov teeb liab sab hauv thiab sab nraud. Raws li cov neeg tswj kev sau ntawv, DELLAs khi rau cov yam ntxwv sau ntawv (TFs) thiab histone H2A los ntawm lawv cov GRAS domains thiab raug xaiv los ua haujlwm rau cov neeg txhawb nqa. Cov kev tshawb fawb tsis ntev los no tau qhia tias DELLA kev ruaj khov yog tswj hwm tom qab kev txhais lus los ntawm ob txoj hauv kev: polyubiquitination induced los ntawm cov tshuaj hormones coggibberellin, uas ua rau lawv qhov kev puas tsuaj sai, thiab kev sib txuas nrog cov khoom siv me me zoo li ubiquitin (SUMO), uas ua rau lawv cov khoom sib sau ua ke ntau ntxiv. Ntxiv mus, DELLA kev ua ub no raug tswj hwm los ntawm ob txoj hauv kev glycosylation sib txawv: O-fucosylation ua rau DELLA-TF sib cuam tshuam, thaum O-linked N-acetylglucosamine (O-GlcNAc) kev hloov pauv inhibits DELLA-TF sib cuam tshuam. Txawm li cas los xij, lub luag haujlwm ntawm DELLA phosphorylation tsis meej vim tias cov kev tshawb fawb yav dhau los tau qhia txog cov txiaj ntsig tsis sib haum xeeb, nrog qee qhov qhia tias phosphorylation txhawb nqa lossis tswj hwm DELLA degradation thiab lwm tus qhia tias phosphorylation tsis cuam tshuam rau lawv qhov ruaj khov. Ntawm no, peb txheeb xyuas cov chaw phosphorylation hauv GA1-3 repressor (RGA), AtDELLA, purified los ntawm Arabidopsis thaliana los ntawm pawg spectrometry thiab qhia tias phosphorylation ntawm ob RGA peptides hauv thaj chaw PolyS thiab PolyS / T txhim kho RGA kev ua ub no los ntawm kev txhawb nqa H2A khi thiab RGA kev koom tes nrog cov neeg txhawb nqa lub hom phiaj. Qhov tseem ceeb, phosphorylation tsis cuam tshuam rau RGA-TF kev sib cuam tshuam lossis RGA ruaj khov. Peb txoj kev tshawb fawb qhia txog lub tshuab molecular uas phosphorylation ua rau DELLA ua haujlwm.
Peb qhov kev tshuaj xyuas spectrometric loj qhia tau hais tias ob qho tib si Pep1 thiab Pep2 tau phosphorylated ntau hauv RGA hauv keeb kwm yav dhau los Ga1 uas tsis muaj GA. Ntxiv rau qhov kev tshawb fawb no, kev tshawb fawb phosphoproteomic kuj tau qhia txog Pep1 phosphorylation hauv RGA, txawm hais tias nws lub luag haujlwm tseem tsis tau kawm53,54,55. Hauv kev sib piv, Pep2 phosphorylation tsis tau piav qhia ua ntej vim tias peptide no tsuas yog tuaj yeem pom siv RGAGKG transgene. Txawm hais tias m1A mutation, uas tshem tawm Pep1 phosphorylation, tsuas yog txo qis me ntsis RGA kev ua haujlwm hauv planta, nws muaj cov txiaj ntsig ntxiv thaum ua ke nrog m2A hauv kev txo qis RGA kev ua haujlwm (Daim Duab Ntxiv 6). Qhov tseem ceeb, Pep1 phosphorylation tau txo qis hauv GA-enhanced sly1 mutant piv rau ga1, qhia tias GA txhawb nqa RGA dephosphorylation, txo nws cov haujlwm. Lub tshuab uas GA suppresses RGA phosphorylation xav tau kev tshawb nrhiav ntxiv. Ib qho ua tau yog tias qhov no tau ua tiav los ntawm kev tswj hwm ntawm cov protein kinase tsis paub. Txawm hais tias kev tshawb fawb tau qhia tias kev qhia tawm ntawm CK1 protein kinase EL1 raug GA txo qis hauv mov41, peb cov txiaj ntsig qhia tau tias kev hloov pauv siab dua ntawm Arabidopsis EL1 homologue (AEL1-4) tsis txo RGA phosphorylation. Hauv kev pom zoo nrog peb cov txiaj ntsig, kev tshawb fawb phosphoproteomic tsis ntev los no siv Arabidopsis AEL overexpressing kab thiab ael triple mutant tsis tau txheeb xyuas cov protein DELLA ua cov substrates ntawm cov kinases no56. Thaum peb npaj cov ntawv sau, nws tau tshaj tawm tias GSK3, lub gene encoding GSK3/SHAGGY-zoo li kinase hauv nplej (Triticum aestivum), tuaj yeem phosphorylate DELLA (Rht-B1b)57, txawm hais tias phosphorylation ntawm Rht-B1b los ntawm GSK3 tsis tau lees paub hauv cog. Cov tshuaj tiv thaiv enzymatic hauv vitro nyob rau hauv qhov muaj GSK3 ua raws li kev tshuaj ntsuam xyuas mass spectrometry qhia tau peb qhov chaw phosphorylation nyob nruab nrab ntawm DELLA thiab GRAS thaj chaw ntawm Rht-B1b (Supplementary Fig. 3). Serine rau alanine hloov pauv ntawm tag nrho peb qhov chaw phosphorylation ua rau Rht-B1b kev ua haujlwm txo qis hauv cov nplej transgenic, sib xws nrog peb cov kev tshawb pom tias alanine hloov pauv hauv Pep2 RGA txo qis RGA kev ua haujlwm. Txawm li cas los xij, hauv vitro protein degradation assays ntxiv qhia tau tias phosphorylation kuj tseem tuaj yeem ruaj khov Rht-B1b57. Qhov no yog qhov sib txawv rau peb cov txiaj ntsig qhia tias alanine hloov pauv hauv Pep2 RGA tsis hloov nws qhov ruaj khov hauv cov nroj tsuag. GSK3 hauv cov nplej yog ib qho ortholog ntawm brassinosteroid-insensitive protein 2 (BIN2) hauv Arabidopsis 57. BIN2 yog tus tswj hwm tsis zoo ntawm BR signaling, thiab BR ua kom nws txoj kev signaling ua haujlwm los ntawm kev ua rau BIN2 degradation 58. Peb tau qhia tias kev kho BR tsis txo RGA stability 59 lossis phosphorylation theem hauv Arabidopsis (Supplementary Figure 2), qhia tias RGA tsis zoo li yuav phosphorylated los ntawm BIN2.
Tag nrho cov ntaub ntawv ntau npaum li cas tau raug tshuaj xyuas los ntawm kev siv Excel, thiab qhov sib txawv tseem ceeb tau txiav txim siab los ntawm kev siv Student's t-test. Tsis muaj cov txheej txheem suav lej tau siv los txiav txim siab ua ntej qhov loj ntawm cov qauv. Tsis muaj cov ntaub ntawv raug tshem tawm ntawm kev tshuaj xyuas; qhov kev sim tsis raug xaiv ua random; thiab cov kws tshawb fawb tau paub txog kev faib tawm thaum lub sijhawm sim thiab kev ntsuas qhov tshwm sim. Qhov loj me ntawm cov qauv tau muab rau hauv cov lus piav qhia thiab hauv cov ntaub ntawv raw.
Lub sijhawm tshaj tawm: Plaub Hlis-15-2025