Your browser doesn't support javascript.
loading
Roles for 3' Phosphoinositides in Macropinocytosis.
Swanson, Joel A; Araki, Nobukazu.
Afiliação
  • Swanson JA; Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA. jswan@umich.edu.
  • Araki N; Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Kagawa, Japan.
Subcell Biochem ; 98: 119-141, 2022.
Article em En | MEDLINE | ID: mdl-35378706
The distinct movements of macropinosome formation and maturation have corresponding biochemical activities which occur in a defined sequence of stages and transitions between those stages. Each stage in the process is regulated by variously phosphorylated derivatives of phosphatidylinositol (PtdIns) which reside in the cytoplasmic face of the membrane lipid bilayer. PtdIns derivatives phosphorylated at the 3' position of the inositol moiety, called 3' phosphoinositides (3'PIs), regulate different stages of the sequence. 3'PIs are synthesized by numerous phosphoinositide 3'-kinases (PI3K) and other lipid kinases and phosphatases, which are themselves regulated by small GTPases of the Ras superfamily. The combined actions of these enzymes localize four principal species of 3'PI to distinct domains of the plasma membrane or to discrete organelles, with distinct biochemical activities confined to those domains. Phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) and phosphatidylinositol (3,4)-bisphosphate (PtdIns(3,4)P2) regulate the early stages of macropinosome formation, which include cell surface ruffling and constrictions of circular ruffles which close into macropinosomes. Phosphatidylinositol 3-phosphate (PtdIns3P) regulates macropinosome fusion with other macropinosomes and early endocytic organelles. Phosphatidylinositol (3,5)-bisphosphate (PtdIns(3,5)P2) mediates macropinosome maturation and shrinkage, through loss of ions and water, and subsequent traffic to lysosomes. The different characteristic rates of macropinocytosis in different cell types indicate levels of regulation which may be governed by the cell's capacity to generate 3'PIs.
Assuntos
Palavras-chave

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Fosfatidilinositóis / Pinocitose Idioma: En Revista: Subcell Biochem Ano de publicação: 2022 Tipo de documento: Article País de afiliação: Estados Unidos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Fosfatidilinositóis / Pinocitose Idioma: En Revista: Subcell Biochem Ano de publicação: 2022 Tipo de documento: Article País de afiliação: Estados Unidos