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Query: EC:3.6.3.1 (
Mg2+-ATPase
)
1,484
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Maintaining lipid membrane integrity is an essential aspect of plant tolerance to high temperature. P
4
-type ATPases are responsible for flipping and stabilizing asymmetric phospholipids in membrane systems, though their functions in stress tolerance are not entirely clear. Aminophospholipid ATPase6 (ALA6) is a member of the P
4
-type ATPase family, which has 12 members in
Arabidopsis thaliana
. Here, we show that a loss-of-function mutant of ALA6 (
ala6
) exhibits clear sensitivity to heat stress, including both basal and acquired thermotolerance treatments. Overexpression of
ALA6
improves seedling resistance to heat stress, while mutated
ALA6
transgenic plants, in which the conserved functional site of the
ALA
family has a point mutation, are still susceptible to heat stress like
ala6
loss-of-function mutant. In addition,
ala6
displays higher ion-leakage during heat treatment, suggesting that the lipid
flippase
activity of ALA6 plays a vital role in heat stress responses. Transcriptome analysis reveals differences in gene expression between
ala6
and wild-type plants with or without heat stress. The differentially expressed genes are involved primarily in the physiological processes of stress response, cellular compartment maintenance, macromolecule stability and energy production. Our results suggest that ALA6 is crucial for the stability of membrane when plants suffer from high temperature stress.
...
PMID:ALA6, a P
4
-type ATPase, Is Involved in Heat Stress Responses in
Arabidopsis thaliana
. 2904 90
Cell polarity is a fundamental feature of all multicellular organisms. PIN auxin transporters are important cell polarity markers that play crucial roles in a plethora of developmental processes in plants. Here, to identify components involved in cell polarity establishment and maintenance in plants, we performed a forward genetic screening of
PIN2
:
PIN1
-
HA
;
pin2
Arabidopsis (
Arabidopsis thaliana
) plants, which ectopically express predominantly basally localized PIN1 in root epidermal cells, leading to agravitropic root growth. We identified the
regulator of PIN polarity 12
(
repp12
) mutation, which restored gravitropic root growth and caused a switch in PIN1-HA polarity from the basal to apical side of root epidermal cells. Next Generation Sequencing and complementation experiments established the causative mutation of
repp12
as a single amino acid exchange in Aminophospholipid ATPase3 (ALA3), a phospholipid
flippase
predicted to function in vesicle formation.
repp12
and
ala3
T-DNA mutants show defects in many auxin-regulated processes, asymmetric auxin distribution, and PIN trafficking. Analysis of quintuple and sextuple mutants confirmed the crucial roles of
ALA
proteins in regulating plant development as well as PIN trafficking and polarity. Genetic and physical interaction studies revealed that ALA3 functions together with the ADP ribosylation factor GTPase exchange factors GNOM and BIG3 in regulating PIN polarity, trafficking, and auxin-mediated development.
...
PMID:Arabidopsis Flippases Cooperate with ARF GTPase Exchange Factors to Regulate the Trafficking and Polarity of PIN Auxin Transporters. 3221 33
Biogenesis of photosynthetic membranes depends on galactolipid synthesis, which relies on several cell compartments, notably the endoplasmic reticulum (ER) and the chloroplast envelope. Galactolipid synthesis involves lipid trafficking between both membrane compartments. In
Arabidopsis
, ALA10, a phospholipid
flippase
of the P
4
type-ATPase family, counteracts the limitation of monogalactosyldiacylglycerol (MGDG) production and has a positive effect on leaf development. ALA10 locates in distinct domains of the ER depending on the ALIS (
ALA
interacting subunit) subunit it interacts with: close to the plasma membrane with ALIS1, or next to chloroplasts with ALIS5. It interacts with FAD2 (Fatty acid desaturase 2) and prevents accumulation of linolenic (18:3) containing phosphatidylcholine (PC) stimulating an increase of MGDG synthesis. Here we report that ALA10 interacts with PUB11 (plant U-box type 11), an E3 protein ubiquitin ligase,
in vitro
and
in vivo
. ALA10 is however ubiquitinated and degraded by the 26S proteasome in a PUB11-independent process. In
pub11
null mutant, the proteasome-dependent degradation of ALA10 is retained and ALA10 is still subject to ubiquitination although its ubiquitination profile appears different. In the absence of PUB11, ALA10 is constrained to the ER close to chloroplasts, which is the usual location when ALA10 is overexpressed. Additionally, in this condition, the decrease of 18:3 containing PC is no longer observed. Taken together these results suggest, that ALA10 contributes in chloroplast-distal ER interacting domains, to reduce the 18:3 desaturation of PC and that PUB11 is involved in reconditioning of ALA10 from chloroplast-proximal to chloroplast-distal ER interacting domains.
...
PMID:PUB11-Dependent Ubiquitination of the Phospholipid Flippase ALA10 Modifies ALA10 Localization and Affects the Pool of Linolenic Phosphatidylcholine. 3276 Apr 18
