72 kDa inositol polyphosphate 5-phosphatase, also known as phosphatidylinositol-4,5-bisphosphate 5-phosphatase or Pharbin, is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

that in humans is encoded by the ''INPP5E''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

Function

INPP5E is a phosphatidylinositol (3,4,5)-trisphosphate (PtdInsP3) and phosphatidylinositol 4,5-bisphosphate 5-phosphatase. Its intracellular localization is the primary

cilium The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike project ...

, a small organelle involved in signal transduction. INPP5E plays a role in hydrolyzing PtdInsP3 produced in response to various growth factors such as

PDGF Platelet-derived growth factor (PDGF) is one among numerous growth factors that regulate cell growth and division. In particular, PDGF plays a significant role in blood vessel formation, the growth of blood vessels from already-existing blood v ...

. Inactivation of the mouse INPP5E gene decreases primary cilia stability, leading to a multiorgan disorder, including absence of eyes,

polydactyly Polydactyly or polydactylism (), also known as hyperdactyly, is an anomaly in humans and animals resulting in supernumerary fingers and/or toes. Polydactyly is the opposite of oligodactyly (fewer fingers or toes). Signs and symptoms In human ...

exencephaly Exencephaly is a type of cephalic disorder wherein the brain is located outside of the skull. This condition is usually found in embryos as an early stage of anencephaly. As an exencephalic pregnancy progresses, the neural tissue gradually degenerat ...

and renal

cyst A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubble) ...

Clinical significance

Mutations in the ''INPP5E'' are associated with MORM syndrome and

Joubert syndrome Joubert syndrome is a rare autosomal recessive genetic disorder that affects the cerebellum, an area of the brain that controls balance and coordination. Joubert syndrome is one of the many genetic syndromes associated with syndromic retinitis pi ...

Function

Clinical significance

References

Further reading