Structural lipids enable the formation of functional oligomers of the eukaryotic purine symporter UapA

TY - JOUR

T1 - Structural lipids enable the formation of functional oligomers of the eukaryotic purine symporter UapA

AU - Pyle, Euan

AU - Amillis, Sotiris

AU - Kalli, Antreas

AU - Hall, Zoe

AU - Lau, Andy Man Chung

AU - Byrne , Bernadette

AU - Hanyaloglu, Aylin C.

AU - Diallinas, George

AU - Politis, Anargyros

PY - 2018/4

Y1 - 2018/4

N2 - The role of membrane lipids in modulating eukaryotic transporter assembly and function remains unclear. We investigated the effect of membrane lipids in the structure and transport activity of the purine transporter UapA, from Aspergillus nidulans. We found that UapA exists mainly as a dimer and that two lipid molecules bind per UapA dimer. We identified three phospholipid classes which co-purified with UapA: phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI). UapA delipidation caused dissociation of the dimer into monomers. Subsequent addition of PI or PE rescued the UapA dimer and allowed recovery of bound lipids, suggesting a central role of these lipids in stabilising the dimer. Molecular dynamics simulations predicted a lipid-binding site near the UapA dimer interface. Mutational analyses established that lipid binding at this site is essential for formation of functional UapA dimers. We propose that structural lipids have a central role in the formation of functional, dimeric UapA.

AB - The role of membrane lipids in modulating eukaryotic transporter assembly and function remains unclear. We investigated the effect of membrane lipids in the structure and transport activity of the purine transporter UapA, from Aspergillus nidulans. We found that UapA exists mainly as a dimer and that two lipid molecules bind per UapA dimer. We identified three phospholipid classes which co-purified with UapA: phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI). UapA delipidation caused dissociation of the dimer into monomers. Subsequent addition of PI or PE rescued the UapA dimer and allowed recovery of bound lipids, suggesting a central role of these lipids in stabilising the dimer. Molecular dynamics simulations predicted a lipid-binding site near the UapA dimer interface. Mutational analyses established that lipid binding at this site is essential for formation of functional UapA dimers. We propose that structural lipids have a central role in the formation of functional, dimeric UapA.

U2 - 10.1016/j.chembiol.2018.03.011

DO - 10.1016/j.chembiol.2018.03.011

M3 - Article

SN - 1074-5521

JO - Chemistry and Biology

JF - Chemistry and Biology

ER -