Faculty Opinions recommendation of The trans-Golgi network accessory protein p56 promotes long-range movement of GGA/clathrin-containing transport carriers and lysosomal enzyme sorting.

2007 ◽  
Author(s):  
Judith Klumperman
Keyword(s):  
Long Range ◽  
Lysosomal Enzyme ◽  
Accessory Protein ◽  
Trans Golgi Network ◽  
Golgi Network

scholarly journals The Trans-Golgi Network Accessory Protein p56 Promotes Long-Range Movement of GGA/Clathrin-containing Transport Carriers and Lysosomal Enzyme Sorting

2007 ◽  
Vol 18 (9) ◽  
pp. 3486-3501 ◽  
Author(s):  
Gonzalo A. Mardones ◽  
Patricia V. Burgos ◽  
Doug A. Brooks ◽  
Emma Parkinson-Lawrence ◽  
Rafael Mattera ◽  
...  
Keyword(s):  
Rna Interference ◽  
Long Range ◽  
Lysosomal Enzyme ◽  
Cathepsin D ◽  
Accessory Protein ◽  
Accessory Proteins ◽  
Acid Hydrolase ◽  
Trans Golgi Network ◽  
Subsequent Capture ◽  
Golgi Network

The sorting of acid hydrolase precursors at the trans-Golgi network (TGN) is mediated by binding to mannose 6-phosphate receptors (MPRs) and subsequent capture of the hydrolase-MPR complexes into clathrin-coated vesicles or transport carriers (TCs) destined for delivery to endosomes. This capture depends on the function of three monomeric clathrin adaptors named GGAs. The GGAs comprise a C-terminal “ear” domain that binds a specific set of accessory proteins. Herein we show that one of these accessory proteins, p56, colocalizes and physically interacts with the three GGAs at the TGN. Moreover, overexpression of the GGAs enhances the association of p56 with the TGN, and RNA interference (RNAi)-mediated depletion of the GGAs decreases the TGN association and total levels of p56. RNAi-mediated depletion of p56 or the GGAs causes various degrees of missorting of the precursor of the acid hydrolase, cathepsin D. In the case of p56 depletion, this missorting correlates with decreased mobility of GGA-containing TCs. Transfection with an RNAi-resistant p56 construct, but not with a p56 construct lacking the GGA-ear–interacting motif, restores the mobility of the TCs. We conclude that p56 tightly cooperates with the GGAs in the sorting of cathepsin D to lysosomes, probably by enabling the movement of GGA-containing TCs.

scholarly journals Ultrastructure of Long-Range Transport Carriers Moving from the trans Golgi Network to Peripheral Endosomes

Traffic ◽  
2006 ◽  
Vol 7 (8) ◽  
pp. 1092-1103 ◽  
Author(s):  
Roman S. Polishchuk ◽  
Enrica San Pietro ◽  
Alessio Di Pentima ◽  
Stefano Teté ◽  
Juan S. Bonifacino
Keyword(s):  
Long Range ◽  
Long Range Transport ◽  
Trans Golgi Network ◽  
Range Transport ◽  
Golgi Network

scholarly journals A Novel Subtype of AP-1-binding Motif within the Palmitoylated trans-Golgi Network/Endosomal Accessory Protein Gadkin/γ-BAR

2009 ◽  
Vol 285 (6) ◽  
pp. 4074-4086 ◽  
Author(s):  
Tanja Maritzen ◽  
Michael R. Schmidt ◽  
Viktoria Kukhtina ◽  
Victoria A. Higman ◽  
Holger Strauss ◽  
...  
Keyword(s):  
Accessory Protein ◽  
Binding Motif ◽  
Trans Golgi Network ◽  
Golgi Network

scholarly journals TIP47 functions in the biogenesis of lipid droplets

2009 ◽  
Vol 185 (4) ◽  
pp. 641-655 ◽  
Author(s):  
Anna V. Bulankina ◽  
Anke Deggerich ◽  
Dirk Wenzel ◽  
Kudzai Mutenda ◽  
Julia G. Wittmann ◽  
...  
Keyword(s):  
Lysosomal Enzyme ◽  
Lipid Droplets ◽  
Current Analysis ◽  
Terminal Sequence ◽  
Interacting Protein ◽  
Trans Golgi Network ◽  
Amino Terminal ◽  
Golgi Network ◽  
Amino Terminal Sequence ◽  
Endocytic Pathways

TIP47 (tail-interacting protein of 47 kD) was characterized as a cargo selection device for mannose 6-phosphate receptors (MPRs), directing their transport from endosomes to the trans-Golgi network. In contrast, our current analysis shows that cytosolic TIP47 is not recruited to organelles of the biosynthetic and endocytic pathways. Knockdown of TIP47 expression had no effect on MPR distribution or trafficking and did not affect lysosomal enzyme sorting. Therefore, our data argue against a function of TIP47 as a sorting device. Instead, TIP47 is recruited to lipid droplets (LDs) by an amino-terminal sequence comprising 11-mer repeats. We show that TIP47 has apolipoprotein-like properties and reorganizes liposomes into small lipid discs. Suppression of TIP47 blocked LD maturation and decreased the incorporation of triacylglycerol into LDs. We conclude that TIP47 functions in the biogenesis of LDs.

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