PtdIns 4-kinasebeta and neuronal calcium sensor-1 co-localize but may not directly associate in mammalian neurons.
It was recently demonstrated that the yeast homologue of phosphatidylinositol 4-kinasebeta PIK1 is directly associated with frq1, the yeast homologue of mammalian neuronal calcium sensor-1 (NCS-1) (Hendricks et al., [1999] Nat. Cell Biol. 1:234- 241). This was a novel finding and suggests that a calcium binding protein activates and regulates PtdIns 4-kinasebeta. This finding had not been shown in mammalian cells and both PtdIns 4-kinasebeta and NCS-1 have been shown to have important roles in the regulation of exocytotic release associated with neurotransmission. The aims of this study were to determine if PtdIns 4-kinasebeta and NCS-1 directly associate in mammalian neural tissues. We show that the immunostaining pattern for PtdIns 4-kinasebeta and NCS-1 is co-localized throughout the neurites of newborn cultured dorsal root ganglia (DRG) neurons but not in E13 DRG neurons. We then provide biochemical evidence that PtdIns 4-kinasebeta may not be in physical association with NCS-1 in mammalian nervous tissue unlike that previously reported in yeast.
Bartlett
S E
SE
Division of Neuroscience, The John Curtin School of Medical Research, Australian National University, Canberra, Australia. selena.bartlett@anu.edu.au
Reynolds
A J
AJ
Weible
M
M
Jeromin
A
A
Roder
J
J
Hendry
I A
IA
D019870:1-Phosphatidylinositol 4-Kinase / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D005727:Ganglia, Spinal / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D016501:Neurites / Q000378:metabolism*; D051580:Neuronal Calcium-Sensor Proteins; D009479:Neuropeptides / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
D002135:Calcium-Binding Proteins; D051580:Neuronal Calcium-Sensor Proteins; D009479:Neuropeptides; D029701:Saccharomyces cerevisiae Proteins; C101464:frequenin calcium sensor proteins; D019870:1-Phosphatidylinositol 4-Kinase; C441760:PIK1 protein, S cerevisiae