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Sterols and sphingolipids differentially function in trafficking of the A rabidopsis ABCB 19 auxin transporter
Author(s) -
Yang Haibing,
Richter Gregory L.,
Wang Xia,
Młodzińska Ewa,
Carraro Nicola,
Ma Guojie,
Jenness Mark,
Chao Daiyin,
Peer Wendy A.,
Murphy Angus S.
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12103
Subject(s) - sphingolipid , microbiology and biotechnology , biology , mutant , arabidopsis , snare complex , atp binding cassette transporter , biochemistry , transporter , gene , membrane , vesicle
Summary The Arabidopsis ATP ‐binding cassette B19 ( ABCB 19, P‐glycoprotein19) transporter functions coordinately with ABCB 1 and PIN 1 to motivate long‐distance transport of the phytohormone auxin from the shoot to root apex. ABCB 19 exhibits a predominantly apolar plasma membrane ( PM ) localization and stabilizes PIN 1 when the two proteins co‐occur. Biochemical evidence associates ABCB 19 and PIN 1 with sterol‐ and sphingolipid‐enriched PM fractions. Mutants deficient in structural sterols and sphingolipids exhibit similarity to abcb19 mutants. Sphingolipid‐defective tsc10a mutants and, to a lesser extent, sterol‐deficient cvp1 mutants phenocopy abcb19 mutants. Live imaging studies show that sterols function in trafficking of ABCB 19 from the trans ‐Golgi network to the PM . Pharmacological or genetic sphingolipid depletion has an even greater impact on ABCB 19 PM targeting and interferes with ABCB 19 trafficking from the Golgi. Our results also show that sphingolipids function in trafficking associated with compartments marked by the VTI 12 syntaxin, and that ABCB 19 mediates PIN 1 stability in sphingolipid‐containing membranes. The TWD 1/ FKBP 42 co‐chaperone immunophilin is required for exit of ABCB 19 from the ER , but ABCB 19 interactions with sterols, sphingolipids and PIN 1 are spatially distinct from FKBP 42 activity at the ER . The accessibility of this system to direct live imaging and biochemical analysis makes it ideal for the modeling and analysis of sterol and sphingolipid regulation of ABCB /P‐glycoprotein transporters.