Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1997 Nov 13;390(6656):192-6.
doi: 10.1038/36621.

A new pathway for synthesis of phosphatidylinositol-4,5-bisphosphate

L E Rameh  1 , K F Tolias, B C Duckworth, L C Cantley
Affiliations

A new pathway for synthesis of phosphatidylinositol-4,5-bisphosphate

L E Rameh et al. Nature. .

Abstract

Phosphatidylinositol-4,5-bisphosphate (PtdIns-4,5-P2), a key molecule in the phosphoinositide signalling pathway, was thought to be synthesized exclusively by phosphorylation of PtdIns-4-P at the D-5 position of the inositol ring. The enzymes that produce PtdIns-4,5-P2 in vitro fall into two related subfamilies (type I and type II PtdInsP-5-OH kinases, or PIP(5)Ks) based on their enzymatic properties and sequence similarities'. Here we have reinvestigated the substrate specificities of these enzymes. As expected, the type I enzyme phosphorylates PtdIns-4-P at the D-5 position of the inositol ring. Surprisingly, the type II enzyme, which is abundant in some tissues, phosphorylates PtdIns-5-P at the D-4 position, and thus should be considered as a 4-OH kinase, or PIP(4)K. The earlier error in characterizing the activity of the type II enzyme is due to the presence of contaminating PtdIns-5-P in commercial preparations of PtdIns-4-P. Although PtdIns-5-P was previously thought not to exist in vivo, we find evidence for the presence of this lipid in mammalian fibroblasts, establishing a new pathway for PtdIns-4,5-P2 synthesis.

PubMed Disclaimer

Comment in

  • Inositol lipid pathways turn turtle.
    Hinchliffe K, Irvine R. Hinchliffe K, et al. Nature. 1997 Nov 13;390(6656):123-4. doi: 10.1038/36458. Nature. 1997. PMID: 9367149 No abstract available.

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

Publication types

MeSH terms

Substances