The role of the phosphoinositides at the Golgi complex

Maria Antonietta De Matteis*, Antonella Di Campli, Anna Godi

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

118 Citations (Scopus)

Abstract

The phosphorylated derivatives of phosphatidylinositol (PtdIns), known as the polyphosphoinositides (PIs), represent key membrane-localized signals in the regulation of fundamental cell processes, such as membrane traffic and cytoskeleton remodelling. The reversible production of the PIs is catalyzed through the combined activities of a number of specific phosphoinositide phosphatases and kinases that can either act separately or in concert on all the possible combinations of the 3, 4, and 5 positions of the inositol ring. So far, seven distinct PI species have been identified in mammalian cells and named according to their site(s) of phosphorylation: PtdIns 3-phosphate (PI3P); PtdIns 4-phosphate (PI4P); PtdIns 5-phosphate (PI5P); PtdIns 3,4-bisphosphate (PI3,4P2); PtdIns 4,5-bisphosphate (PI4,5P2); PtdIns 3,5-bisphosphate (PI3,5P2); and PtdIns 3,4,5-trisphosphate (PI3,4,5P3). Over the last decade, accumulating evidence has indicated that the different PIs serve not only as intermediates in the synthesis of the higher phosphorylated phosphoinositides, but also as regulators of different protein targets in their own right. These regulatory actions are mediated through the direct binding of their protein targets. In this way, the PIs can control the subcellular localization and activation of their various effectors, and thus execute a variety of cellular responses. To exert these functions, the metabolism of the PIs has to be finely regulated both in time and space, and this is achieved by controlling the subcellular distribution, regulation, and activation states of the enzymes involved in their synthesis and removal (kinases and phosphatases). These exist in many different isoforms, each of which appears to have a distinctive intracellular localization and regulation. As a consequence of this subcompartimentalized PI metabolism, a sort of "PI-fingerprint" of each cell membrane compartment is generated. When combined with the targeted recruitment of their protein effectors and the different intracellular distributions of other lipids and regulatory proteins (such as small GTPases), these factors can maintain and determine the identity of the cell organelles despite the extensive membrane flux [S. Munro, Organelle identity and the organization of membrane traffic, Nat. Cell. Biol. 6 (2004) 469-4721]. Here, we provide an overview of the regulation and roles of different phosphoinositide kinases and phosphatases and their lipid products at the Golgi complex.

Original languageEnglish
Pages (from-to)396-405
Number of pages10
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1744
Issue number3 SPEC. ISS.
DOIs
Publication statusPublished - 10 Jul 2005
Externally publishedYes

Keywords

  • Golgi complex
  • Lipid binding module
  • Phosphoinositide

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