Mannose-6-phosphate pathway: A review on its role in lysosomal function and dysfunction

• Type: Another Publication in an International Scientific Journal
• Date: 2012

Authors

Maria Francisca Coutinho (Author) Other; Maria Joao Prata (Author) FCUP; Sandra Alves (Author) Other

Journal

Title: Molecular Genetics and Metabolism

Vol. 105

Pages: 542-550

ISSN: 1096-7192

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 135 Citations

Scopus - 150 Citations

Scientific classification

FOS: Medical and Health sciences > Other medical sciences

Other information

Authenticus ID: P-002-BRK

DOI: 10.1016/j.ymgme.2011.12.012

Abstract (EN): Lysosomal hydrolases are synthesized in the rough endoplasmic reticulum and specifically transported through the Golgi apparatus to the trans-Golgi network, from which transport vesicles bud to deliver them to the endosomal/lysosomal compartment. The explanation of how are the lysosomal enzymes accurately recognized and selected over many other proteins in the trans-Golgi network relies on being tagged with a unique marker: the mannose-6-phosphate (M6P) group, which is added exclusively to the N-linked oligosaccharides of lysosomal soluble hydrolases, as they pass through the cis-Golgi network. Generation of the M6P recognition marker depends on a reaction involving two different enzymes: UDP-N-acetylglucosamine 1-phosphotransferase and alpha-N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase. The M6P groups are then recognized by two independent transmembrane M6P receptors, present in the trans-Golgi network: the cation-independent M6P receptor and/or the cation-dependent M6P receptor. These proteins bind to lysosomal hydrolases on the lumenal side of the membrane and to adaptins in assembling clathrin coats on the cytosolic side. In this way, the M6P receptors help package the hydrolases into vesicles that bud from the trans-Golgi network to deliver their contents to endosomes that ultimately will develop into mature lysosomes, where recently-delivered hydrolases may start digesting the endocyted material. The above described process is known as the M6P-dependent pathway and is responsible for transporting most lysosomal enzymes. This review synthesizes the current knowledge on each of the major proteins involved in the M6P-dependent pathway. Impairments in this pathway will also be addressed, highlighting the lysosomal storage disorders associated to GlcNAc-1-phosphotransferase loss of function: mucolipidosis type II and III.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9