The diversity and possible functions of the inositol polyphosphate 5-phosphatases.

Abstract

Distinct forms of inositol and phosphatidylinositol polyphosphate 5-phosphatases selectively remove the phosphate from the 5-position of the inositol ring from both soluble and lipid substrates, i.e., inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), inositol 1,3,4, 5-tetrakisphosphate (Ins(1,3,4,5)P4), phosphatidylinositol 4, 5-bisphosphate (PtdIns(4,5)P2) or phosphatidylinositol 3,4, 5-trisphosphate (PtdIns(3,4,5)P3). In mammalian cells, this family contains a series of distinct genes and splice variants. All inositol polyphosphate 5-phosphatases share a 5-phosphatase domain and various protein modules probably responsible for specific cell localisation or recruitment (SH2 domain, proline-rich sequences, prenylation sites, etc.). Type I Ins(1,4,5)P3 5-phosphatase also uses Ins(1,3,4,5)P4 but not the phosphoinositides as substrates. This enzyme is targeted to specific membranes by means of a prenylation site. Type II 5-phosphatases can use both PtdIns(4,5)P2 and PtdIns(3,4,5)P3 as substrates. Five mammalian enzymes and multiple splice variants are known: INPP5P or inositol polyphosphate 5-phosphatase II, OCRL (a Golgi protein implicated in the Lowe oculocerebrorenal syndrome), synaptojanin (a protein involved in the recycling of synaptic vesicles), SHIP 1 and SHIP 2 (or SH2-containing inositol 5-phosphatases). As discussed in this review, the substrate specificity, regulatory mechanisms, subcellular localisation and tissue specificity indicate that the different 5-phosphatase isoforms may play specific roles. As known in the dephosphorylation of tyrosine containing substrates by the tyrosine protein phosphatases or in the metabolism of cyclic nucleotides by the cyclic nucleotide phosphodiesterases, inositol polyphosphate 5-phosphatases directly participate in the control of second messengers in response to both activation or inhibitory cell signalling.

• Authors: C Erneux, C Govaerts, D Communi, X Pesesse
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 1436 Issue 1-2 Pg. 185-99 (Dec 08 1998) ISSN: 0006-3002 [Print] Netherlands
• PMID: 9838104 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Nerve Tissue Proteins
• Phosphatidylinositol 4,5-Diphosphate
• Phosphatidylinositol Phosphates
• phosphatidylinositol 3,4,5-triphosphate
• Inositol 1,4,5-Trisphosphate
• synaptojanin
• Phosphoric Monoester Hydrolases
• Inositol Polyphosphate 5-Phosphatases
• INPP5D protein, human
• Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases

Topics

• Amino Acid Sequence
• Animals
• Cell Membrane (enzymology)
• Cytosol (enzymology)
• Humans
• Inositol 1,4,5-Trisphosphate (metabolism)
• Inositol Polyphosphate 5-Phosphatases
• Molecular Sequence Data
• Nerve Tissue Proteins (metabolism)
• Phosphatidylinositol 4,5-Diphosphate (metabolism)
• Phosphatidylinositol Phosphates (metabolism)
• Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
• Phosphoric Monoester Hydrolases (chemistry, genetics, metabolism, physiology)
• Protein Prenylation
• Second Messenger Systems
• Substrate Specificity