Gamma-BAR, a novel AP-1-interacting protein involved in post-Golgi trafficking.
A novel peripheral membrane protein (2c18) that interacts directly with the gamma 'ear' domain of the adaptor protein complex 1 (AP-1) in vitro and in vivo is described. Ultrastructural analysis demonstrates a colocalization of 2c18 and gamma1-adaptin at the trans-Golgi network (TGN) and on vesicular profiles. Overexpression of 2c18 increases the fraction of membrane-bound gamma1-adaptin and inhibits its release from membranes in response to brefeldin A. Knockdown of 2c18 reduces the steady-state levels of gamma1-adaptin on membranes. Overexpression or downregulation of 2c18 leads to an increased secretion of the lysosomal hydrolase cathepsin D, which is sorted by the mannose-6-phosphate receptor at the TGN, which itself involves AP-1 function for trafficking between the TGN and endosomes. This suggests that the direct interaction of 2c18 and gamma1-adaptin is crucial for membrane association and thus the function of the AP-1 complex in living cells. We propose to name this protein gamma-BAR.
Neubrand
Veronika E
VE
Cell Biology and Cell Biophysics Programme, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
Will
Rainer D
RD
Möbius
Wiebke
W
Poustka
Annemarie
A
Wiemann
Stefan
S
Schu
Peter
P
Dotti
Carlos G
CG
Pepperkok
Rainer
R
Simpson
Jeremy C
JC
D033961:Adaptor Protein Complex 1 / Q000378:metabolism*; D033982:Adaptor Protein Complex gamma Subunits / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002402:Cathepsin D / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure; D002522:Chlorocebus aethiops; D015536:Down-Regulation; D011992:Endosomes / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D008969:Molecular Sequence Data; D021381:Protein Transport / Q000502:physiology; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques; D014709:Vero Cells; D021601:trans-Golgi Network / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure
C500885:AP1AR protein, human; D033961:Adaptor Protein Complex 1; D033982:Adaptor Protein Complex gamma Subunits; D008565:Membrane Proteins; D002402:Cathepsin D