ITPK1 mediates the lipid-independent synthesis of inositol phosphates controlled by metabolism.
Proc Natl Acad Sci U S A
; 116(49): 24551-24561, 2019 12 03.
Article
em En
| MEDLINE
| ID: mdl-31754032
ABSTRACT
Inositol phosphates (IPs) comprise a network of phosphorylated molecules that play multiple signaling roles in eukaryotes. IPs synthesis is believed to originate with IP3 generated from PIP2 by phospholipase C (PLC). Here, we report that in mammalian cells PLC-generated IPs are rapidly recycled to inositol, and uncover the enzymology behind an alternative "soluble" route to synthesis of IPs. Inositol tetrakisphosphate 1-kinase 1 (ITPK1)-found in Asgard archaea, social amoeba, plants, and animals-phosphorylates I(3)P1 originating from glucose-6-phosphate, and I(1)P1 generated from sphingolipids, to enable synthesis of IP6 We also found using PAGE mass assay that metabolic blockage by phosphate starvation surprisingly increased IP6 levels in a ITPK1-dependent manner, establishing a route to IP6 controlled by cellular metabolic status, that is not detectable by traditional [3H]-inositol labeling. The presence of ITPK1 in archaeal clades thought to define eukaryogenesis indicates that IPs had functional roles before the appearance of the eukaryote.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fosfotransferases (Aceptor do Grupo Álcool)
/
Fosfatos de Inositol
Limite:
Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Reino Unido