Golgi protein FAPP2 tubulates membranes.
The Golgi-associated four-phosphate adaptor protein 2 (FAPP2) has been shown to possess transfer activity for glucosylceramide both in vitro and in cells. We have previously shown that FAPP2 is involved in apical transport from the Golgi complex in epithelial MDCK cells. In this paper we assign an unknown activity for the protein as well as providing structural insight into protein assembly and a low-resolution envelope structure. By applying analytical ultracentrifugation and small-angle x-ray scattering, we show that FAPP2 is a dimeric protein in solution, having a curved shape 30 nm in length. The purified FAPP2 protein has the capability to form tubules from membrane sheets in vitro. This activity is dependent on the phosphoinositide-binding activity of the PH domain of FAPP2. These data suggest that FAPP2 functions directly in the formation of apical carriers in the trans-Golgi network.
Cao
Xinwang
X
Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany.
Coskun
Unal
U
Rössle
Manfred
M
Buschhorn
Sabine B
SB
Grzybek
Michal
M
Dafforn
Timothy R
TR
Lenoir
Marc
M
Overduin
Michael
M
Simons
Kai
K
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D002460:Cell Line; D004285:Dogs; D008051:Lipid Bilayers / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D012996:Solutions; D021601:trans-Golgi Network
D048868:Adaptor Proteins, Signal Transducing; D008051:Lipid Bilayers; C487038:PLEKHA8 protein, human; D010716:Phosphatidylinositols; D012996:Solutions