A phosphatidylinositol phosphate-specific myo-inositol polyphosphate 5-phosphatase required for seedling growth

A phosphatidylinositol phosphate-specific myo-inositol polyphosphate 5-phosphatase required for... The phosphatidylinositol phosphate signaling pathway is involved in many crucial cellular functions. The myo-inositol polyphosphate 5-phosphatases (5PTases) (E.C. 3.1.3.56) comprise a large protein family that hydrolyze 5-phosphates from a variety of phosphatidylinositol phosphate and inositol phosphate substrates. We previously reported that the At5PTase11 enzyme (At1g47510), which is one of the smallest predicted 5PTases found in any organism, encodes an active 5PTase whose activity is restricted to tris- and bis-, but not mono-phosphorylated phosphatidylinositol phosphate substrates containing a 5-phosphate. This is in contrast to other unrestricted Arabidopsis 5PTases, which also hydrolyze tris- and bis inositol phosphate molecules. To further explore the function of At5PTase11, we have characterized two T-DNA mutants in the At5PTase11 gene, and have complemented this mutant. Seed from 5ptase11 mutants germinate slower than wildtype seed and mutant seedlings have decreased hypocotyl growth as compared to wildtype seedlings when grown in the dark. This phenotype is the opposite of the increased hypocotyl growth phenotype previously described for other 5ptase mutants defective in inositol phosphate-specific 5PTase enzymes. By labeling the endogenous myo-inositol pool in 5ptase11 mutants, we correlated these hypocotyl growth changes with a small increase in the 5PTase11 substrate, phosphatidylinositol (4,5) bisphosphate, and decreases in the potential products of 5PTase11, phosphatidylinositol (3) phosphate and phosphatidylinositol (4) phosphate. Surprisingly, we also found that dark-grown 5ptase11 mutants contain increases in inositol (1,4,5) trisphosphate and an inositol bisphosphate that is not a substrate for recombinant 5PTase11. We present a model for regulation of hypocotyl growth by specific molecules found in this pathway. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Plant Molecular Biology Springer Journals

A phosphatidylinositol phosphate-specific myo-inositol polyphosphate 5-phosphatase required for seedling growth

Loading next page...
 
/lp/springer_journal/a-phosphatidylinositol-phosphate-specific-myo-inositol-polyphosphate-5-PVqc0c1PTS
Publisher
Springer Netherlands
Copyright
Copyright © 2008 by Springer Science+Business Media B.V.
Subject
Life Sciences; Plant Pathology; Biochemistry, general; Plant Sciences
ISSN
0167-4412
eISSN
1573-5028
D.O.I.
10.1007/s11103-008-9327-3
Publisher site
See Article on Publisher Site

Abstract

The phosphatidylinositol phosphate signaling pathway is involved in many crucial cellular functions. The myo-inositol polyphosphate 5-phosphatases (5PTases) (E.C. 3.1.3.56) comprise a large protein family that hydrolyze 5-phosphates from a variety of phosphatidylinositol phosphate and inositol phosphate substrates. We previously reported that the At5PTase11 enzyme (At1g47510), which is one of the smallest predicted 5PTases found in any organism, encodes an active 5PTase whose activity is restricted to tris- and bis-, but not mono-phosphorylated phosphatidylinositol phosphate substrates containing a 5-phosphate. This is in contrast to other unrestricted Arabidopsis 5PTases, which also hydrolyze tris- and bis inositol phosphate molecules. To further explore the function of At5PTase11, we have characterized two T-DNA mutants in the At5PTase11 gene, and have complemented this mutant. Seed from 5ptase11 mutants germinate slower than wildtype seed and mutant seedlings have decreased hypocotyl growth as compared to wildtype seedlings when grown in the dark. This phenotype is the opposite of the increased hypocotyl growth phenotype previously described for other 5ptase mutants defective in inositol phosphate-specific 5PTase enzymes. By labeling the endogenous myo-inositol pool in 5ptase11 mutants, we correlated these hypocotyl growth changes with a small increase in the 5PTase11 substrate, phosphatidylinositol (4,5) bisphosphate, and decreases in the potential products of 5PTase11, phosphatidylinositol (3) phosphate and phosphatidylinositol (4) phosphate. Surprisingly, we also found that dark-grown 5ptase11 mutants contain increases in inositol (1,4,5) trisphosphate and an inositol bisphosphate that is not a substrate for recombinant 5PTase11. We present a model for regulation of hypocotyl growth by specific molecules found in this pathway.

Journal

Plant Molecular BiologySpringer Journals

Published: Apr 8, 2008

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off