X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    SAC phosphoinositide phosphatases at the tonoplast mediate vacuolar function in Arabidopsis
    Proceedings of the National Academy of Sciences ; 2014
    In:  Proceedings of the National Academy of Sciences Vol. 111, No. 7 ( 2014-02-18), p. 2818-2823
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 111, No. 7 ( 2014-02-18), p. 2818-2823
    Abstract: Phosphatidylinositol (PtdIns) is a structural phospholipid that can be phosphorylated into various lipid signaling molecules, designated polyphosphoinositides (PPIs). The reversible phosphorylation of PPIs on the 3, 4, or 5 position of inositol is performed by a set of organelle-specific kinases and phosphatases, and the characteristic head groups make these molecules ideal for regulating biological processes in time and space. In yeast and mammals, PtdIns3P and PtdIns(3,5)P 2 play crucial roles in trafficking toward the lytic compartments, whereas the role in plants is not yet fully understood. Here we identified the role of a land plant-specific subgroup of PPI phosphatases, the suppressor of actin 2 (SAC2) to SAC5, during vacuolar trafficking and morphogenesis in Arabidopsis thaliana . SAC2–SAC5 localize to the tonoplast along with PtdIns3P, the presumable product of their activity. In SAC gain- and loss-of-function mutants, the levels of PtdIns monophosphates and bisphosphates were changed, with opposite effects on the morphology of storage and lytic vacuoles, and the trafficking toward the vacuoles was defective. Moreover, multiple sac knockout mutants had an increased number of smaller storage and lytic vacuoles, whereas extralarge vacuoles were observed in the overexpression lines, correlating with various growth and developmental defects. The fragmented vacuolar phenotype of sac mutants could be mimicked by treating wild-type seedlings with PtdIns(3,5)P 2 , corroborating that this PPI is important for vacuole morphology. Taken together, these results provide evidence that PPIs, together with their metabolic enzymes SAC2–SAC5, are crucial for vacuolar trafficking and for vacuolar morphology and function in plants.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1324264111
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2014
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Online Resource
    Open Access Request
    Availability (electronic / print)
  • 2
    Online Resource
    Online Resource
    Asymmetric gibberellin signaling regulates vacuolar trafficking of PIN auxin transporters during root gravitropism
    Proceedings of the National Academy of Sciences ; 2013
    In:  Proceedings of the National Academy of Sciences Vol. 110, No. 9 ( 2013-02-26), p. 3627-3632
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 110, No. 9 ( 2013-02-26), p. 3627-3632
    Abstract: Gravitropic bending of plant organs is mediated by an asymmetric signaling of the plant hormone auxin between the upper and lower side of the respective organ. Here, we show that also another plant hormone, gibberellic acid (GA), shows asymmetric action during gravitropic responses. Immunodetection using an antibody against GA and monitoring GA signaling output by downstream degradation of DELLA proteins revealed an asymmetric GA distribution and response with the maximum at the lower side of gravistimulated roots. Genetic or pharmacological manipulation of GA levels or response affects gravity-mediated auxin redistribution and root bending response. The higher GA levels at the lower side of the root correlate with increased amounts of PIN-FORMED2 (PIN2) auxin transporter at the plasma membrane. The observed increase in PIN2 stability is caused by a specific GA effect on trafficking of PIN proteins to lytic vacuoles that presumably occurs downstream of brefeldin A-sensitive endosomes. Our results suggest that asymmetric auxin distribution instructive for gravity-induced differential growth is consolidated by the asymmetric action of GA that stabilizes the PIN-dependent auxin stream along the lower side of gravistimulated roots.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1300107110
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2013
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Online Resource
    Open Access Request
    Availability (electronic / print)
  • 3
    Online Resource
    Online Resource
    Switching desaturase enzyme specificity by alternate subcellular targeting
    Proceedings of the National Academy of Sciences ; 2004
    In:  Proceedings of the National Academy of Sciences Vol. 101, No. 28 ( 2004-07-13), p. 10266-10271
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 101, No. 28 ( 2004-07-13), p. 10266-10271
    Abstract: The functionality, substrate specificity, and regiospecificity of enzymes typically evolve by the accumulation of mutations in the catalytic portion of the enzyme until new properties arise. However, emerging evidence suggests enzyme functionality can also be influenced by metabolic context. When the plastidial Arabidopsis 16:0Δ 7 desaturase FAD5 (ADS3) was retargeted to the cytoplasm, regiospecificity shifted 70-fold, Δ 7 to Δ 9 . Conversely, retargeting of two related cytoplasmic 16:0Δ 9 Arabidopsis desaturases (ADS1 and ADS2) to the plastid, shifted regiospecificity ≈25-fold, Δ 9 to Δ 7 . All three desaturases exhibited Δ 9 regiospecificity when expressed in yeast, with desaturated products found predominantly on phosphatidylcholine. Coexpression of each enzyme with cucumber monogalactosyldiacylglycerol (MGDG) synthase in yeast conferred Δ 7 desaturation, with 16:1Δ 7 accumulating specifically on the plastidial lipid MGDG. Positional analysis is consistent with ADS desaturation of 16:0 on MGDG. The lipid headgroup acts as a molecular switch for desaturase regiospecificity. FAD5 Δ 7 regiospecificity is thus attributable to plastidial retargeting of the enzyme by addition of a transit peptide to a cytoplasmic Δ 9 desaturase rather than the numerous sequence differences within the catalytic portion of ADS enzymes. The MGDG-dependent desaturase activity enabled plants to synthesize 16:1Δ 7 and its abundant metabolite, 16:3Δ 7,10,13 . Bioinformatics analysis of the Arabidopsis genome identified 239 protein families that contain members predicted to reside in different subcellular compartments, suggesting alternative targeting is widespread. Alternative targeting of bifunctional or multifunctional enzymes can exploit eukaryotic subcellular organization to create metabolic diversity by permitting isozymes to interact with different substrates and thus create different products in alternate compartments.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0402200101
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2004
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Online Resource
    Open Access Request
    Availability (electronic / print)
  • 4
    Online Resource
    Online Resource
    Transient and sustained increases in inositol 1,4,5-trisphosphate precede the differential growth response in gravistimulated maize pulvini
    Proceedings of the National Academy of Sciences ; 1999
    In:  Proceedings of the National Academy of Sciences Vol. 96, No. 10 ( 1999-05-11), p. 5838-5843
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 96, No. 10 ( 1999-05-11), p. 5838-5843
    Abstract: The internodal maize pulvinus responds to gravistimulation with differential cell elongation on the lower side. As the site of both graviperception and response, the pulvinus is an ideal system to study how organisms sense changes in orientation. We observed a transient 5-fold increase in inositol 1,4,5-trisphosphate (IP 3 ) within 10 s of gravistimulation in the lower half of the pulvinus, indicating that the positional change was sensed immediately. Over the first 30 min, rapid IP 3 fluctuations were observed between the upper and lower halves. Maize plants require a presentation time of between 2 and 4 h before the cells on the lower side of the pulvinus are committed to elongation. After 2 h of gravistimulation, the lower half consistently had higher IP 3, and IP 3 levels on the lower side continued to increase up to ≈5-fold over basal levels before visible growth. As bending became visible after 8–10 h, IP 3 levels returned to basal values. Additionally, phosphatidylinositol 4-phosphate 5-kinase activity in the lower pulvinus half increased transiently within 10 min of gravistimulation, suggesting that the increased IP 3 production was accompanied by an up-regulation of phosphatidylinositol 4,5-bisphosphate biosynthesis. Neither IP 3 levels nor phosphatidylinositol 4-phosphate 5-kinase activity changed in pulvini halves from vertical control plants. Our data indicate the involvement of IP 3 and inositol phospholipids in both short- and long-term responses to gravistimulation. As a diffusible second messenger, IP 3 provides a mechanism to transmit and amplify the signal from the perceiving to the responding cells in the pulvinus, coordinating a synchronized growth response.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.96.10.5838
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 1999
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Online Resource
    Open Access Request
    Availability (electronic / print)
  • 5
    Online Resource
    Online Resource
    Modulating seed β-ketoacyl-acyl carrier protein synthase II level converts the composition of a temperate seed oil to that of a palm-like tropical oil
    Proceedings of the National Academy of Sciences ; 2007
    In:  Proceedings of the National Academy of Sciences Vol. 104, No. 11 ( 2007-03-13), p. 4742-4747
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 104, No. 11 ( 2007-03-13), p. 4742-4747
    Abstract: β-Ketoacyl-acyl carrier protein (ACP) synthase II (KASII) elongates 16:0-ACP to 18:0-ACP in the plastid, where it competes with three other enzymes at the first major branch point in fatty acid biosynthesis. Despite its key metabolic location, the influence of KASII in determining seed oil composition remains unclear, in part because the biochemical consequences of the fab1-1 mutation were unresolved. Thus, fab1-1 , and a newly identified knockout allele, fab1-2 , were analyzed in the context of the hypothesis that modulating KASII activity is sufficient to convert the composition of a temperate seed oil into that of a palm-like tropical oil. No homozygous fab1-2 individuals were identified in progeny of self-fertilized heterozygous fab1-2 plants, ≈1/4 of which aborted before the torpedo stage, suggesting that fab1-2 represents a complete loss of function and results in lethality when homozygous. Consistent with this hypothesis, homozygous fab1-2 plants were identified when a fab1-1 transgene was introduced, demonstrating that fab1-1 encodes an active KASII. Strong seed-specific hairpin-RNAi reductions in FAB1 expression resulted in abortion of ≈1/4 of the embryos in an apparent phenocopy of fab1-2 homozygosity. In less severe FAB1 hairpin-RNAi individuals, embryos developed normally and exhibited a 1:2:1 segregation ratio for palmitate accumulation. Thus, early embryo development appears sensitive to elevated 16:0, whereas at later stages, up to 53% of 16:0, i.e., a 7-fold increase over wild-type levels, is tolerated. These results resolve the role of KASII in seed metabolism and demonstrate that modulation of Arabidopsis KASII levels is sufficient to convert its temperate oilseed composition to that of a palm-like tropical oil.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0611141104
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2007
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Online Resource
    Open Access Request
    Availability (electronic / print)
Nothing or not found what you are looking for? Please check your search query or use the Interlibrary Loan Search.
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages