title: The potato sucrose transporter StSUT1 interacts with a DRM-associated protein disulfide isomerase.
abstract: Organization of proteins into complexes is crucial for many cellular functions. Recently, the SUT1 protein was shown to form homodimeric complexes, to be associated with lipid raft-like microdomains in yeast as well as in plants and to undergo endocytosis in response to brefeldin A. We therefore aimed to identify SUT1-interacting proteins that might be involved in dimerization, endocytosis, or targeting of SUT1 to raft-like microdomains. Therefore, we identified potato membrane proteins, which are associated with the detergent-resistant membrane (DRM) fraction. Among the proteins identified, we clearly confirmed StSUT1 as part of DRM in potato source leaves. We used the yeast two-hybrid split ubiquitin system (SUS) to systematically screen for interaction between the sucrose transporter StSUT1 and other membrane-associated or soluble proteins in vivo. The SUS screen was followed by immunoprecipitation using affinity-purified StSUT1-specific peptide antibodies and mass spectrometric analysis of co-precipitated proteins. A large overlap was observed between the StSUT1-interacting proteins identified in the co-immunoprecipitation and the detergent-resistant membrane fraction. One of the SUT1-interacting proteins, a protein disulfide isomerase (PDI), interacts also with other sucrose transporter proteins. A potential role of the PDI as escort protein is discussed.
authors: Institute of Biology, Department of Plant Physiology, Humboldt University, 10115 Berlin, Germany.
authors: Undine
authors: U
authors: Krügel
authors: Hong-Xia
authors: HX
authors: He
authors: Konstanze
authors: K
authors: Gier
authors: Jana
authors: J
authors: Reins
authors: Izabela
authors: I
authors: Chincinska
authors: Bernhard
authors: B
authors: Grimm
authors: Waltraud X
authors: WX
authors: Schulze
authors: Christina
authors: C
authors: Kühn
mesh_terms: D002462:Cell Membrane / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D019704:Protein Disulfide-Isomerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011198:Solanum tuberosum / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; D010940:Plant Proteins; D013395:Sucrose; D019704:Protein Disulfide-Isomerases