Disease relevance of SUC2

• The sink-source transition in tobacco leaves was studied noninvasively using transgenic plants expressing the green-fluorescent protein (GFP) under control of the Arabidopsis thaliana SUC2 promoter, and also by imaging transgenic plants that constitutively expressed a tobacco mosaic virus movement protein (MP) fused to GFP (MP-GFP) [1].

High impact information on SUC2

• PmSUC3: characterization of a SUT2/SUC3-type sucrose transporter from Plantago major [2].
• Arguments for and against a potential sensor function for this type of sucrose transporter are presented, and the role of this type of transporter in the regulation of sucrose fluxes is discussed [2].
• Analyses of the AtSUC2 promoter-GFP plants demonstrated that the 27-kD GFP protein can traffic through plasmodesmata from companion cells into sieve elements and migrate within the phloem [3].
• In addition, turanose and alpha-methylglucoside induced small but significant inward currents indicating that they were transported by At-SUC2 [4].
• Substrate specificity of the Arabidopsis thaliana sucrose transporter AtSUC2 [4].

Biological context of SUC2

• The ability of AtSUC9 to transport 10 glucosides was compared directly with that of AtSUC2, HvSUT1 (from barley [Hordeum vulgare]), and ShSUT1 (from sugarcane [Saccharum hybrid]), and results indicate that type I and type II Suc transporters have different substrate specificities [5].
• Arabidopsis Sucrose Transporter AtSUC9. High-Affinity Transport Activity, Intragenic Control of Expression, and Early Flowering Mutant Phenotype [5].
• The DNA sequence of the SUC2 promoter has been determined [6].
• Companion cell protoplasts, which could be recognized by their nucleus, vacuole and chloroplasts, and by their expression of the phloem-specific marker genes SUC2 and AHA3, formed the basis for a cell-specific cDNA library and expressed sequence tag (EST) collection [7].
• This paper describes the sites of AtSUC1 gene expression and AtSUC1 protein localization and assigns specific functions to this sucrose transporter in anther development and pollen tube growth [8].

Anatomical context of SUC2

• This paper describes functional expression in Saccharomyces cerevisiae of two cDNAs encoding energy-dependent sucrose transporters from the plasma membrane of Arabidopsis thaliana, SUC1 and SUC2 [9].
• By expression of AtSUC2 in Xenopus oocytes and two-electrode voltage clamping, we have tested the ability of AtSUC2 to transport a range of physiological and synthetic glucosides [4].
• The companion cell-specific Arabidopsis disaccharide carrier AtSUC2 is expressed in nematode-induced syncytia [10].

Associations of SUC2 with chemical compounds

• AtSUC9 showed low substrate specificity, similar to AtSUC2 (At1g22710), and transported a wide range of glucosides, including helicin, salicin, arbutin, maltose, fraxin, esculin, turanose, and alpha-methyl-d-glucose [5].
• SUC1 and SUC2: two sucrose transporters from Arabidopsis thaliana; expression and characterization in baker's yeast and identification of the histidine-tagged protein [9].
• A possible regulatory effect of carbohydrates (glucose and sucrose) on the activity of the SUC2 promoter was studied and excluded, both in excised leaves and young seedlings of transgenic Arabidopsis plants [6].
• AtSUC2 is the first disaccharide carrier described to be activated by pathogens [10].
• Results support the idea that AtSUC2 mediates the transmembrane transfer of Suc [10].

Regulatory relationships of SUC2

• The overall pattern of SUC2-GUS expression correlated well with that of the Arabidopsis thaliana AHA3 plasma-membrane H(+)-ATPase which is also expressed in the phloem and most likely represents the primary pump generating the energy for secondary active transporters such as SUC2 [6].

Other interactions of SUC2

• The two proteins exhibit different patterns of pH dependence with SUC1 being much more active at neutral and slightly acidic pH values than SUC2 [9].
• AtSUC3, a gene encoding a new Arabidopsis sucrose transporter, is expressed in cells adjacent to the vascular tissue and in a carpel cell layer [11].
• The sucrose transporter gene AtSUC5 was studied as part of a programme aimed at identifying and studying the genes involved in seed maturation in Arabidopsis [12].
• On the other hand, expression of the sucrose transporter is inducible by auxin and cytokinin but not by sucrose [13].

Analytical, diagnostic and therapeutic context of SUC2

• ELISA assays run with microsomal fractions and PMV using the AtSUC1 sucrose transporter probe indicated that ageing, and to a lesser extent cutting, increased the amount of sucrose transporter present in the plasma membrane [14].
• K+ channels from Arabidopsis phloem cells expressing green fluorescent protein (GFP) under the control of the AtSUC2 promoter were analysed using the patch-clamp technique and quantitative RT-PCR [7].

References