Loss of the cisternal organelle in the axon initial segment of cortical neurons in synaptopodin-deficient mice.
Standard
Loss of the cisternal organelle in the axon initial segment of cortical neurons in synaptopodin-deficient mice. / Carlos, Bas Orth; Schultz, Christian; Müller, Christian M; Frotscher, Michael; Deller, Thomas.
In: J COMP NEUROL, Vol. 504, No. 5, 5, 2007, p. 441-449.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
Harvard
APA
Vancouver
Bibtex
}
RIS
TY - JOUR
T1 - Loss of the cisternal organelle in the axon initial segment of cortical neurons in synaptopodin-deficient mice.
AU - Carlos, Bas Orth
AU - Schultz, Christian
AU - Müller, Christian M
AU - Frotscher, Michael
AU - Deller, Thomas
PY - 2007
Y1 - 2007
N2 - The axon initial segment of cortical neurons contains the so-called cisternal organelle, an enigmatic formation of stacked endoplasmic reticulum and interdigitating plates of electron-dense material. This organelle shows many structural similarities to the spine apparatus, a cellular organelle found in a subpopulation of dendritic spines. Whereas roles in calcium signaling and protein trafficking have been proposed for the spine apparatus, little is yet known about the physiological function of its putative axonal counterpart. Considering the structural similarity of these two organelles, we hypothesized that synaptopodin, a protein essential for the formation of the dendritic spine apparatus, could also be a component of the cisternal organelle. By using immunofluorescence microscopy, we found that synaptopodin is indeed located within the axon initial segments of principal neurons in the mouse neocortex and hippocampus. Pre-embedding immunogold labeling demonstrated a close association of synaptopodin immunoreactivity with the dense plates of cisternal organelles. In synaptopodin-deficient mice, ultrastructural analysis of identified axon initial segments of CA1 pyramidal cells revealed a lack of cisternal organelles similar to the reported lack of spine apparatuses in these mutants. However, in vitro patch clamp recording of mutant neurons showed that the lack of cisternal organelles did not lead to any changes in basic electrophysiological parameters of action potentials. Taken together, our data demonstrate that synaptopodin is an essential component of the cisternal organelle of axons and of the dendritic spine apparatus, two organelles that are structurally and molecularly related.
AB - The axon initial segment of cortical neurons contains the so-called cisternal organelle, an enigmatic formation of stacked endoplasmic reticulum and interdigitating plates of electron-dense material. This organelle shows many structural similarities to the spine apparatus, a cellular organelle found in a subpopulation of dendritic spines. Whereas roles in calcium signaling and protein trafficking have been proposed for the spine apparatus, little is yet known about the physiological function of its putative axonal counterpart. Considering the structural similarity of these two organelles, we hypothesized that synaptopodin, a protein essential for the formation of the dendritic spine apparatus, could also be a component of the cisternal organelle. By using immunofluorescence microscopy, we found that synaptopodin is indeed located within the axon initial segments of principal neurons in the mouse neocortex and hippocampus. Pre-embedding immunogold labeling demonstrated a close association of synaptopodin immunoreactivity with the dense plates of cisternal organelles. In synaptopodin-deficient mice, ultrastructural analysis of identified axon initial segments of CA1 pyramidal cells revealed a lack of cisternal organelles similar to the reported lack of spine apparatuses in these mutants. However, in vitro patch clamp recording of mutant neurons showed that the lack of cisternal organelles did not lead to any changes in basic electrophysiological parameters of action potentials. Taken together, our data demonstrate that synaptopodin is an essential component of the cisternal organelle of axons and of the dendritic spine apparatus, two organelles that are structurally and molecularly related.
KW - Animals
KW - Male
KW - Mice
KW - Mice, Inbred C57BL
KW - Mice, Knockout
KW - Cerebral Cortex cytology
KW - Hippocampus cytology
KW - Microfilament Proteins deficiency
KW - Neurons cytology
KW - Action Potentials genetics
KW - Axons ultrastructure
KW - Endoplasmic Reticulum metabolism
KW - Microscopy, Immunoelectron methods
KW - Patch-Clamp Techniques methods
KW - Spectrin metabolism
KW - Animals
KW - Male
KW - Mice
KW - Mice, Inbred C57BL
KW - Mice, Knockout
KW - Cerebral Cortex cytology
KW - Hippocampus cytology
KW - Microfilament Proteins deficiency
KW - Neurons cytology
KW - Action Potentials genetics
KW - Axons ultrastructure
KW - Endoplasmic Reticulum metabolism
KW - Microscopy, Immunoelectron methods
KW - Patch-Clamp Techniques methods
KW - Spectrin metabolism
M3 - SCORING: Zeitschriftenaufsatz
VL - 504
SP - 441
EP - 449
JO - J COMP NEUROL
JF - J COMP NEUROL
SN - 0021-9967
IS - 5
M1 - 5
ER -
