PUBLICATION

Inositol hexakisphosphate kinase-2 acts as an effector of the vertebrate Hedgehog pathway

Authors

Sarmah, B., and Wente, S.R.

ID

ZDB-PUB-101101-11

Date

2010

Source

Proceedings of the National Academy of Sciences of the United States of America 107(46): 19921-19926 (Journal)

Registered Authors

Keywords

diphosphoryl inositol tetrakisphosphate, ipk2, inositol polyphosphate multikinase, inositol pentakisphosphate, inositol hexakisphosphate

MeSH Terms

Phosphotransferases (Phosphate Group Acceptor)/metabolism*
NIH 3T3 Cells
Gene Expression Regulation, Developmental
Gene Knockdown Techniques
Zebrafish Proteins/metabolism*
Hedgehog Proteins/metabolism*
Zebrafish/embryology
Zebrafish/genetics
Zebrafish/metabolism*
Inositol Phosphates/metabolism
Somites/abnormalities
Somites/enzymology
Somites/pathology
Animals
Cell Movement
Craniofacial Abnormalities/embryology
Craniofacial Abnormalities/enzymology
Craniofacial Abnormalities/pathology
Embryo, Mammalian/enzymology
Embryo, Mammalian/pathology
Embryonic Development/genetics
Mice
Signal Transduction*
Neural Crest/enzymology
Neural Crest/pathology

(all 25)

PubMed

20980661 Full text @ Proc. Natl. Acad. Sci. USA

Abstract

Inositol phosphate (IP) kinases constitute an emerging class of cellular kinases linked to multiple cellular activities. Here, we report a previously uncharacterized cellular function in Hedgehog (Hh) signaling for the IP kinase designated inositol hexakisphosphate kinase-2 (IP6K2) that produces diphosphoryl inositol phosphates (PP-IPs). In zebrafish embryos, IP6K2 activity was required for normal development of craniofacial structures, somites, and neural crest cells. ip6k2 depletion in both zebrafish and mammalian cells also inhibited Hh target gene expression. Inhibiting IP(6) kinase activity using N(2)-(m-(trifluoromethy)lbenzyl) N(6)-(p-nitrobenzyl)purine (TNP) resulted in altered Hh signal transduction. In zebrafish, restoring IP6K2 levels with exogenous ip6k2 mRNA reversed the effects of IP6K2 depletion. Furthermore, overexpression of ip6k2 in mammalian cells enhanced the Hh pathway response, suggesting IP6K2 is a positive regulator of Hh signaling. Perturbations from IP6K2 depletion or TNP were reversed by overexpressing smoM2, gli1, or ip6k2. Moreover, the inhibitory effect of cyclopamine was reversed by overexpressing ip6k2. This identified roles for the inositol kinase pathway in early vertebrate development and tissue morphogenesis, and in Hh signaling. We propose that IP6K2 activity is required at the level or downstream of Smoothened but upstream of the transcription activator Gli1.

Genes / Markers

Figures

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Expression

Fish	Conditions	Stage	Anatomy	Assay	Figure
WT	control	26+ somites	neural crest	ISH	Fig. 2
WT + MO1-ip6k2a	standard conditions	26+ somites	neural crest	ISH	Fig. 2
WT	control	26+ somites	neural crest	ISH	Fig. 2
WT + MO1-ip6k2a	standard conditions	26+ somites	neural crest	ISH	Fig. 2
WT	control	1-4 somites	neural crest	ISH	Fig. 2
WT + MO1-ip6k2a	standard conditions	1-4 somites	neural crest	ISH	Fig. 2
WT	control	Prim-5	somite	ISH	Fig. 3
WT + MO3-ip6k2a	standard conditions	Prim-5	somite	ISH	Fig. 3
WT	standard conditions	75%-epiboly	axis	ISH	Fig. S2
WT	standard conditions	Pec-fin	central nervous system	ISH	Fig. S2

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Phenotype

Fish	Conditions	Stage	Phenotype	Figure
WT + MO1-ip6k2a	standard conditions	1-4 somites	neural crest cell fate specification process quality, normal	Fig. 2
WT + MO1-ip6k2a	standard conditions	10-13 somites	neural crest cell decreased amount, abnormal	Fig. 2
WT + MO1-ip6k2a	standard conditions	10-13 somites	neural crest cell development disrupted, abnormal	Fig. 2
WT + MO1-ip6k2a	standard conditions	26+ somites	neural crest cell migration disrupted, abnormal	Fig. 2
WT + MO1-ip6k2a	standard conditions	26+ somites	neural crest cell position, abnormal	Fig. 2
WT + MO1-ipmkb	standard conditions	Day 5	cranium hypoplastic, abnormal	Fig. 1
WT + MO1-ipmkb	standard conditions	Day 5	embryonic viscerocranium morphogenesis disrupted, abnormal	Fig. 1
WT + MO1-ippk	standard conditions	Day 5	determination of heart left/right asymmetry disrupted, abnormal	Fig. 1
WT + MO3-ip6k2a	standard conditions	Prim-5	head decreased size, abnormal	Fig. 1
WT + MO3-ip6k2a	standard conditions	Prim-5	slow muscle cell decreased amount, abnormal	Fig. 3

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Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
vu234Tg	Tg(sox10:mRFP)	Transgenic Insertion

Human Disease / Model

Sequence Targeting Reagents

Target	Reagent	Reagent Type
ip6k2a	MO1-ip6k2a	MRPHLNO
ip6k2a	MO2-ip6k2a	MRPHLNO
ip6k2a	MO3-ip6k2a	MRPHLNO
ipmkb	MO1-ipmkb	MRPHLNO
ippk	MO1-ippk	MRPHLNO

Fish

Fish
vu234Tg
vu234Tg + MO1-ip6k2a
WT
WT + MO1-ip6k2a
WT + MO1-ipmkb
WT + MO1-ippk
WT + MO3-ip6k2a

Antibodies

Orthology

Engineered Foreign Genes

Marker	Marker Type	Name
mRFP	EFG	mRFP

Mapping

Sarmah et al., 2010 ZDB-PUB-101101-11 PMID:20980661

Inositol hexakisphosphate kinase-2 acts as an effector of the vertebrate Hedgehog pathway

Sarmah et al., 2010

ZDB-PUB-101101-11
PMID:20980661