Format

Send to

Choose Destination
J Cell Sci. 2017 Oct 15;130(20):3447-3454. doi: 10.1242/jcs.200857. Epub 2017 Sep 4.

Loss of OCRL increases ciliary PI(4,5)P2 in Lowe oculocerebrorenal syndrome.

Author information

1
Stanford University, Department of Ophthalmology, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94304, USA.
2
Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
3
Stanford University, Department of Ophthalmology, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94304, USA yangsun@stanford.edu.
4
Palo Alto Veterans Administration, Palo Alto, CA 94304, USA.

Abstract

Lowe syndrome is a rare X-linked disorder characterized by bilateral congenital cataracts and glaucoma, mental retardation, and proximal renal tubular dysfunction. Mutations in OCRL, an inositol polyphosphate 5-phosphatase that dephosphorylates PI(4,5)P2, cause Lowe syndrome. Previously we showed that OCRL localizes to the primary cilium, which has a distinct membrane phospholipid composition, but disruption of phosphoinositides in the ciliary membrane is poorly understood. Here, we demonstrate that cilia from Lowe syndrome patient fibroblasts exhibit increased levels of PI(4,5)P2 and decreased levels of PI4P. In particular, subcellular distribution of PI(4,5)P2 build-up was observed at the transition zone. Accumulation of ciliary PI(4,5)P2 was pronounced in mouse embryonic fibroblasts (MEFs) derived from Lowe syndrome mouse model as well as in Ocrl-null MEFs, which was reversed by reintroduction of OCRL. Similarly, expression of wild-type OCRL reversed the elevated PI(4,5)P2 in Lowe patient cells. Accumulation of sonic hedgehog protein in response to hedgehog agonist was decreased in MEFs derived from a Lowe syndrome mouse model. Together, our findings show for the first time an abnormality in ciliary phosphoinositides of both human and mouse cell models of Lowe syndrome.

KEYWORDS:

Lowe syndrome; OCRL; PI(4,5)P2; Phosphoinositide; Primary cilia; Sonic hedgehog

PMID:
28871046
PMCID:
PMC5665444
DOI:
10.1242/jcs.200857
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center