1 / 32

6. Ca 2+ -ATPases , another group of P-type ATPase, are

ATP. Ca 2+. ATP. ADP+P i. H +. Ca 2+. Ca 2+. Ca 2+. ADP+P i. Ca 2+ /H+ antiporter. ATP. ATP. Ca 2+. Ca 2+. Ca 2+. Ca 2+. Ca 2+. Ca 2+ channel. Ca 2+ channel. ADP+P i. ADP+P i. 6. Ca 2+ -ATPases , another group of P-type ATPase, are

anika-morris
Download Presentation

6. Ca 2+ -ATPases , another group of P-type ATPase, are

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ATP Ca2+ ATP ADP+Pi H+ Ca2+ Ca2+ Ca2+ ADP+Pi Ca2+ /H+ antiporter ATP ATP Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ channel Ca2+ channel ADP+Pi ADP+Pi 6. Ca2+-ATPases, another group of P-type ATPase, are distributed among various plant membranes. Ca2+ channel Vacuole Golgi PM Ca2+ channel Nucleus ER

  2. 1 4 5 10 1 4 5 10 COOH COOH Ca2+ Ca2+ Auto- inhibitor NH2 Asp-P Asp-P CaM-Binding NH2 ATP-binding ATP-binding Structural Characteristic of Ca2+-ATPases ER-type Calcium ATPases (ECAs) Autoinhibited Calcium ATPases (ACAs)

  3. Autoinhibited Ca2+- ATPase (ACA) ER group ACA7 ACA2 ACA1 ACA11 Vacuole group ACA4 ACA10 ACA8 ACA9 ACA13 ACA12 PM group Unknown group

  4. Localization of ACA11 in Arabidopsis Protoplast GFP RFP DIC Merge Free GFP (Cytosol) 35S-ACA8-GFP (PM) 35S-ACA11-GFP (Vacuole)

  5. Phenotype of vacuole Ca2+ pump mutants (aca4/aca11)

  6. Complementation of the aca11/aca4mutant with the ACA11 gene

  7. Cell death in aca4/aca11 is a HR-like PCD Lactophenol cleaning (Phenolic compound) Anilline blue staining (callose) WT KO Bright Bright UV UV

  8. EM Photos of aca4/aca11 mutants V V V W.T W.T x60 V V V #316 #316 #316

  9. Recovery phenotype of aca11/aca4 mutant by phosphate Transfer to soil after growth in MSO media for 10 days

  10. Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Pi Pi Pi Pi Pi Pi Pi Pi Pi Pi Pi Pi Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Hypothesis chloroplast chloroplast Nucleus ER Golgi Cell Death Signal??? VPE activation chloroplast membrane collapse Plasma membrane Cell Death

  11. 7. Vacuolar and other membranes are energized through vacuolar H+-ATPase V1 sector pH 7.5 V0 sector pH 5.5 (pH 3.0) Structural model of V-type H+-ATPase

  12. Function of V-type H+-ATPases • Plant vacuole contains a highly acidic solution, with pH 5.5. • Proton pumping into the vacuolar lumen not only energizes the membrane for carrier-mediated transport but also generates the low pH of the vacuole. • An acidic lumemal pH is thought to contribute to • vesicle trafficking And protein targeting. • These enzymes are present in membranes from th ER, Golgi, • and coated vesicles of plant cells

  13. The H+-ATPase are potently and specifically inhibited by the macrolide antibiotic bafilomycin A1

  14. 8. The plant vacuolar membrane also possesses a unique H+-pumping inorganic pyrophosphatase (H+-ppase) PPi  2 pi

  15. 9. ABC-type pumps are emerging as major players in sequestration of amphipathic metabolites and xenotoxics into the vacuole ABC: ATP binding cassette

  16. Transport of a glutathione-conjugated xenotoxic and a chlorophyll Catabolite by AtMRP2, and ABC transporter from Arabidpsis.

  17. Cd2+detoxificationpathway in yeast and plant cytoplasm Glu+Cys GCS γ-GluCys +Gly Cd2+ GS Cd(GSH)2 GSH sulfide PCS YCF1 PC sulfide Cd2+ LMW LMW HMW Cd- PC Cd- PC Cd- PC HMT1 vacuole Christopher S.C. et al(2000)

  18. 3.4. Carriers

  19. Carriers exhibit Michaelis-Menten kinetics • that indicate conformational changes during transport. Carriers exhibit saturation kinetics.

  20. Carriers undergo conformational changes during transport (ex, The activity of carrier C)

  21. 2. Carriers translocate a wide variety of inorganic and small organic soluteswith high specificity. 1) Inorganic nutrients: NH4+, NO3-, Pi, K+, SO42-, Cl- 2) Organic solutes: sugars, amino acids, purine and pyrimidine bases

  22. Functions of carriers 1. At plasma membrane, - nutrient uptake - the mobilization and storage of metabolites. 2. At endomembrane, - sequestration of ions (Na+, Ca2+, Mg2+, No3-, sugars, aa)

  23. 3. Most plant carriers are energized by coupling to pmf.

  24. 4. Molecular identification of carriers defines them as members of the major facilitator superfamily • Functional analysis • Yeast complementation • Protein expression in Oocytes

  25. Observation of plant carriers expressed in heterologous systems can provide into carrier function

  26. Structural model illustrating the orientation of a generalized carrier in a membrane

  27. Localization of the sucrose transporter SUC2 to companion cells of the phloem • Immunofluorescent localization of SUC2 in Arabidopsis stems. • Same section as in A but viewed with transmitted light. • P: phloem X: xylem

  28. Localization of the sucrose transporter SUT1 to sieve elements • Immunofluorescent localization of SUT1 in a longitudinal section of a potato stems. • Silver-enhanced Immunogold localization of SUT1 in cross-section of a potato petiole • sp: sieve plate n: nucleus cc: companion cells

  29. 6. Regulation of carrier activity 1) By transcriptional control 2) By post-translationalcontrol

  30. Different transcription of AtKUP2 and AtKUP3 Low K+: 40uM, High K+: 2mM

  31. 7.In some cases, ion-coupled solute transport involves Na+ rather than H+ 1. Na+ symport have been found. a. Uptake of NO3- and some amino acids is Na+-dependent b. uptake of K+ at micromolar concentration is also Na+-dependent 2. Na+coupling of K+ transport has been proved by a wheat cDNA

  32. Acetabularia, a marine algae

More Related