Amillis, S.

Diallinas, G.

Karachaliou, M.

Yalelis, V.

Digital Repository of Hellenic Managing Authority of the Operational Programme &quot;Education and Lifelong Learning&quot; (EDULLL)

In search for a role of oligomerization of a purine transporter in a model fungal system Karachaliou M.. Amillis S.. Yialelis V. and Diallinas G. National and Kapodistrian University of Athens / Faculty of Biology. Athens Running title: Role of oligomerization of a purine transporter The uric acid/xanthine transporter UapA of the model fungus Aspergillus niduians has been used as a prototype cargo to studymembranetrafficking andendocytosis. Inthepresence of ammonium ions or substrates UapA is ubiquitinated, internalized from the PM and sorted into the MVB/vacuolar pathway. Interestingly, substrate-elicited endocytosis operates only for functional UapA molecules or for inactiveUapAversions co-expressed with active UapA molecules. The latter phenomenon, called in rrarcs-endocytosis. prompted us to investigate whether UapA oligomerizes. Here, we confirm that UapA oj^gomerizes using two different approaches; reconstitution of split ΥΈΡ parts attached to UapA (BiFC assay) and by direct co-immunoprecipitation. Subsequently, using results from a systematic analysis oftheN-tailofUapA. we select sp ecific mut ant s showing ER-retent ion and show that UapA oligomerizationtakes place in the ER membrane. Thus. UapA oligomerization might serve either for ER-exit and trafficking to theplasma membrane, without excluding a role in the function and turnover of UapA^»er se. To approach these issues, we genetically selected suppressors of an ER-retained mutant, which are located in transmembrane segments (TMS) 7 and 11-12. Our findings are better explained with the hypothesis that the N-tail of UapA ajkjtsjjencahy affects the structure of UapA so that it also affects its oligomerization. which in turn might affect trafficking and/or turnover. At present we examine the possible role of the Secl3/Sec23-24 ER-exit molecular machinery on UapA oligomerization and vice versa. Oligomerization has been observed in a number of plant and mammaliantransporters. including those involved in neurotransmission, showing that it constitutes an evolutionary conserved mechanism for the fine regulation of transporters. In search for a role of oligomerization of ai Bur in^tra nsporter ih a model funga I system •-·-;-· •Authored by Μ , Karachaliou, S . Amillis, V. Yialelis and &. Diallinas UA wt Sh · /π Ernas endocytosis o f Uaj>A„, fllcA UapA-YFPc U-PATGFP ν*Ρ**ΡΡπ U-^VFPn u i p A-U«, A-GFP lupA-Hi ES i-Mis ia- t îH* a-l l ix e-OhP As due to UapA olieomerizatian. • * * -nniitJiiiiTi'ïiini μι t u ι \*t-tru«t*Mhtn -tireutlCHÏD'iBFLFiPAPri"^ " " rjTtlHBl.GimiYGFlFRFti.Pf I 1 mVw,V<Ttimil.GflYTlVGri FRPtl.Pf i u b k * r * i u - i m i M i τ i.i y »ι - ' 'llEDGtirinïDÏGfLFTPHLPf _ -Tl«M.IMlTtlrfrrLFTrWrf - fw»tf*(vi -llKFUVrJIÏHÏHri F Π R[l Y 11 τ -f HCDfLlIiUTUïSUL-KFÏE^ Il l*LTlXEHirJirnïHFIFTPhlPFU •ïr M«rt" •£ υ^ ρΑΔ •uçQ&kpQ :·υ : o S «t Ï<TA/ : S V298A V4TA ; V*7Af i F41TC An N-taij motif functionally interacting with;TMS 7 and JMS 11 affects LjâgA localization in the plasma membrane or its turnover. Is this interaction related to ya^pjggmenzatigjj? UiSA-YFP, Uaf]A-YFPr OYDT'A-YFP, DYDYIA-YFP. J · · · DYOYIfvYFP, UapA-YFPn Intronsexocyjtgsis, of UajgA . Üaj^ghgpmgnzatign already initiates fromthe ER membrane. Is it necessary for concent rat ive Sec23/24-dependenl ER-exit? : UapA oligomeriiation,.. v instiate in the ΕΛ membrane and is Rossibh? criticai for. F-fVe* localisation in PM or/and turnover, ^ might be controlled by N-tail interactions with specific TMS domains ... *i»Hh*Eurerfinlln· 

In search for a role of oligomerization of a purine transporter in a model fungal system

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In search for a role of oligomerization of a purine transporter in a model fungal system

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Digital Repository of Hellenic Managing Authority of the Operational Programme "Education and Lifelong Learning" (EDULLL)

In search for a role of oligomerization of a purine transporter in a model fungal system

Abstract

Similar works

Full text

Available Versions

Digital Repository of Hellenic Managing Authority of the Operational Programme &quot;Education and Lifelong Learning&quot; (EDULLL)

Digital Repository of Hellenic Managing Authority of the Operational Programme "Education and Lifelong Learning" (EDULLL)