TY - JOUR
T1 - Phosphatidylinositol-4-kinase type II α is a component of adaptor protein-3-derived vesicles
AU - Salazar, Gloria
AU - Craige, Branch
AU - Wainer, Bruce H.
AU - Guo, Jim
AU - De Camilli, Pietro
AU - Faundez, Victor
PY - 2005/8
Y1 - 2005/8
N2 - A membrane fraction enriched in vesicles containing the adaptor protein (AP)-3 cargo zinc transporter 3 was generated from PC12 cells and was used to identify new components of these organelles by mass spectrometry. Proteins prominently represented in the fraction included AP-3 subunits, synaptic vesicle proteins, and lysosomal proteins known to be sorted in an AP-3-dependent way or to interact genetically with AP-3. A protein enriched in this fraction was phosphatidylinositol-4-kinase type IIα (PI4KIIα). Biochemical, pharmacological, and morphological analyses supported the presence of PI4KIIα in AP-3-positive organelles. Furthermore, the subcellular localization of PI4KIIα was altered in cells from AP-3-deficient mocha mutant mice. The PI4KIIα normally present both in perinuclear and peripheral organelles was substantially decreased in the peripheral membranes of AP-3-deficient mocha fibroblasts. In addition, as is the case for other proteins sorted in an AP-3-dependent way, PI4KIIα content was strongly reduced in nerve terminals of mocha hippocampal mossy fibers. The functional relationship between AP-3 and PI4KIIα was further explored by PI4KIIα knockdown experiments. Reduction of the cellular content of PI4KIIα strongly decreased the punctate distribution of AP-3 observed in PC12 cells. These results indicate that PI4KIIα is present on AP-3 organelles where it regulates AP-3 function.
AB - A membrane fraction enriched in vesicles containing the adaptor protein (AP)-3 cargo zinc transporter 3 was generated from PC12 cells and was used to identify new components of these organelles by mass spectrometry. Proteins prominently represented in the fraction included AP-3 subunits, synaptic vesicle proteins, and lysosomal proteins known to be sorted in an AP-3-dependent way or to interact genetically with AP-3. A protein enriched in this fraction was phosphatidylinositol-4-kinase type IIα (PI4KIIα). Biochemical, pharmacological, and morphological analyses supported the presence of PI4KIIα in AP-3-positive organelles. Furthermore, the subcellular localization of PI4KIIα was altered in cells from AP-3-deficient mocha mutant mice. The PI4KIIα normally present both in perinuclear and peripheral organelles was substantially decreased in the peripheral membranes of AP-3-deficient mocha fibroblasts. In addition, as is the case for other proteins sorted in an AP-3-dependent way, PI4KIIα content was strongly reduced in nerve terminals of mocha hippocampal mossy fibers. The functional relationship between AP-3 and PI4KIIα was further explored by PI4KIIα knockdown experiments. Reduction of the cellular content of PI4KIIα strongly decreased the punctate distribution of AP-3 observed in PC12 cells. These results indicate that PI4KIIα is present on AP-3 organelles where it regulates AP-3 function.
UR - http://www.scopus.com/inward/record.url?scp=23044514633&partnerID=8YFLogxK
U2 - 10.1091/mbc.E05-01-0020
DO - 10.1091/mbc.E05-01-0020
M3 - Article
C2 - 15944223
AN - SCOPUS:23044514633
SN - 1059-1524
VL - 16
SP - 3692
EP - 3704
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 8
ER -