Domain requirement for the membrane trafficking and targeting of syntaxin 1A.
Syntaxin plays a key role in intracellular membrane fusion in eukaryotic cells. The function of syntaxin relies on its proper trafficking to and targeting at the target membrane. The mechanisms underlying the trafficking and targeting of syntaxin to its physiological sites remain poorly understood. Here we have analyzed the trafficking of syntaxin 1A in INS-1 and CHO cells. We have identified the transmembrane domain together with several flanking positive-charged amino acids as the minimal domain required for the membrane delivery. Interestingly, we found that SNARE motif-exposed syntaxin 1A mutants were retained in endoplasmic reticulum (ER) and failed to transport to the cell surface in the absence of SNAP-25, suggesting that the exposure of the SNARE motif causes ER retention and complexation with SNAP-25 helps the ER escape. Finally, our data propose two key roles for the H(abc) domain: to protect nonspecific interaction by masking the SNARE motif and to participate in the clustering of syntaxin 1A to the fusion sites in the plasma membrane.
Yang
Xiaofei
X
Joint Laboratory of Institute of Biophysics & Huazhong University of Science and Technology, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
Xu
Pingyong
P
Xiao
Yang
Y
Xiong
Xiong
X
Xu
Tao
T
D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology; D051379:Mice; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D050825:Synaptosomal-Associated Protein 25 / Q000378:metabolism; D050827:Syntaxin 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D011994:Recombinant Proteins; D050825:Synaptosomal-Associated Protein 25; D050827:Syntaxin 1