Limits...
Mobile DHHC palmitoylating enzyme mediates activity-sensitive synaptic targeting of PSD-95.

Noritake J, Fukata Y, Iwanaga T, Hosomi N, Tsutsumi R, Matsuda N, Tani H, Iwanari H, Mochizuki Y, Kodama T, Matsuura Y, Bredt DS, Hamakubo T, Fukata M - J. Cell Biol. (2009)

Bottom Line: We found that blocking synaptic activity rapidly induces PSD-95 palmitoylation and mediates synaptic clustering of PSD-95 and associated AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-type glutamate receptors.Upon activity blockade, DHHC2 translocates to the postsynaptic density to transduce this effect.These data demonstrate that individual DHHC members are differentially regulated and that dynamic recruitment of protein palmitoylation machinery enables compartmentalized regulation of protein trafficking in response to extracellular signals.

View Article: PubMed Central - PubMed

Affiliation: Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.

ABSTRACT
Protein palmitoylation is the most common posttranslational lipid modification; its reversibility mediates protein shuttling between intracellular compartments. A large family of DHHC (Asp-His-His-Cys) proteins has emerged as protein palmitoyl acyltransferases (PATs). However, mechanisms that regulate these PATs in a physiological context remain unknown. In this study, we efficiently monitored the dynamic palmitate cycling on synaptic scaffold PSD-95. We found that blocking synaptic activity rapidly induces PSD-95 palmitoylation and mediates synaptic clustering of PSD-95 and associated AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-type glutamate receptors. A dendritically localized DHHC2 but not the Golgi-resident DHHC3 mediates this activity-sensitive palmitoylation. Upon activity blockade, DHHC2 translocates to the postsynaptic density to transduce this effect. These data demonstrate that individual DHHC members are differentially regulated and that dynamic recruitment of protein palmitoylation machinery enables compartmentalized regulation of protein trafficking in response to extracellular signals.

Show MeSH

Related in: MedlinePlus

Model for compartmentalized synaptic palmitoylation of PSD-95 by mobile DHHC2. (A) Certain palmitoylated proteins such as the Gα subunit shuttle between the plasma membrane and the Golgi in nonpolarized cells. Golgi-resident DHHC3 and a putative PPT at the plasma membrane can mediate this constitutive shuttling. In neurons, DHHC3 localizes at the Golgi apparatus and mediates constitutive palmitoylation of various substrates, including Gα and PSD-95. (B and C) PSD-95 shuttling in dendrites. (B) A dynamic equilibrium exists between palmitoylated postsynaptic PSD-95 and nonpalmitoylated cytosolic PSD-95. Depalmitoylated PSD-95 diffuses into the spine and dendritic shaft. DHHC2 PAT mainly localizes in dendritic shafts on vesicles and mediates dendritic PSD-95 palmitoylation. PSD, postsynaptic density. (C) When synaptic activity is blocked, DHHC2 vesicles move into spines. This translocated DHHC2 palmitoylates spinous PSD-95; the increased postsynaptic PSD-95 thereby contributes to AMPAR homeostasis.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC2712995&req=5

fig8: Model for compartmentalized synaptic palmitoylation of PSD-95 by mobile DHHC2. (A) Certain palmitoylated proteins such as the Gα subunit shuttle between the plasma membrane and the Golgi in nonpolarized cells. Golgi-resident DHHC3 and a putative PPT at the plasma membrane can mediate this constitutive shuttling. In neurons, DHHC3 localizes at the Golgi apparatus and mediates constitutive palmitoylation of various substrates, including Gα and PSD-95. (B and C) PSD-95 shuttling in dendrites. (B) A dynamic equilibrium exists between palmitoylated postsynaptic PSD-95 and nonpalmitoylated cytosolic PSD-95. Depalmitoylated PSD-95 diffuses into the spine and dendritic shaft. DHHC2 PAT mainly localizes in dendritic shafts on vesicles and mediates dendritic PSD-95 palmitoylation. PSD, postsynaptic density. (C) When synaptic activity is blocked, DHHC2 vesicles move into spines. This translocated DHHC2 palmitoylates spinous PSD-95; the increased postsynaptic PSD-95 thereby contributes to AMPAR homeostasis.

Mentions: Recent fluorescence recovery after photobleaching and photoconversion analyses revealed that several palmitoylated proteins such as Harvey Ras/neuroblastoma Ras (Rocks et al., 2005), Gαo (Chisari et al., 2007), and Gαq (Tsutsumi et al., 2009) rapidly shuttle between the plasma membrane and the Golgi apparatus. This constitutive shuttling comprises four steps: (1) palmitoylation by the Golgi-resident DHHC proteins, (2) trafficking to the plasma membrane, (3) depalmitoylation by a putative PPT and rapid cytosolic diffusion, and (4) transient trapping at the Golgi for repalmitoylation (Fig. 8 A; Rocks et al., 2006; Tsutsumi et al., 2009). In neurons, where the Golgi apparatus is segregated from the axon and dendrites, we suggest that Golgi-localized DHHC3 mediates the constitutive palmitoylation of PSD-95 at the cell body. In dendrites, PSD-95 depalmitoylated at the postsynaptic membrane diffuses from dendritic spine to shaft, is repalmitoylated on DHHC2-positive vesicles, and is redirected to postsynaptic membranes (Fig. 8 B). When synaptic activity is blocked, DHHC2 vesicles translocate from dendritic shafts to sites near the postsynaptic membrane. This allows DHHC2 to repalmitoylate PSD-95 in the spine (Fig. 8 C). Thus, mobile DHHC2 induces a local increase of PSD-95 palmitoylation, which leads to AMPAR recruitment. We propose that extracellular signals translocate specific DHHC PATs and create a new route for substrate shuttling between loci of palmitoylation and depalmitoylation, leading to efficient and precise substrate targeting. Such a compartmentalized regulatory mechanism of DHHC PATs may contribute to spatiotemporal regulation of signaling molecules in polarized neurons, epithelial cells, and migrating cells.


Mobile DHHC palmitoylating enzyme mediates activity-sensitive synaptic targeting of PSD-95.

Noritake J, Fukata Y, Iwanaga T, Hosomi N, Tsutsumi R, Matsuda N, Tani H, Iwanari H, Mochizuki Y, Kodama T, Matsuura Y, Bredt DS, Hamakubo T, Fukata M - J. Cell Biol. (2009)

Model for compartmentalized synaptic palmitoylation of PSD-95 by mobile DHHC2. (A) Certain palmitoylated proteins such as the Gα subunit shuttle between the plasma membrane and the Golgi in nonpolarized cells. Golgi-resident DHHC3 and a putative PPT at the plasma membrane can mediate this constitutive shuttling. In neurons, DHHC3 localizes at the Golgi apparatus and mediates constitutive palmitoylation of various substrates, including Gα and PSD-95. (B and C) PSD-95 shuttling in dendrites. (B) A dynamic equilibrium exists between palmitoylated postsynaptic PSD-95 and nonpalmitoylated cytosolic PSD-95. Depalmitoylated PSD-95 diffuses into the spine and dendritic shaft. DHHC2 PAT mainly localizes in dendritic shafts on vesicles and mediates dendritic PSD-95 palmitoylation. PSD, postsynaptic density. (C) When synaptic activity is blocked, DHHC2 vesicles move into spines. This translocated DHHC2 palmitoylates spinous PSD-95; the increased postsynaptic PSD-95 thereby contributes to AMPAR homeostasis.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2712995&req=5

fig8: Model for compartmentalized synaptic palmitoylation of PSD-95 by mobile DHHC2. (A) Certain palmitoylated proteins such as the Gα subunit shuttle between the plasma membrane and the Golgi in nonpolarized cells. Golgi-resident DHHC3 and a putative PPT at the plasma membrane can mediate this constitutive shuttling. In neurons, DHHC3 localizes at the Golgi apparatus and mediates constitutive palmitoylation of various substrates, including Gα and PSD-95. (B and C) PSD-95 shuttling in dendrites. (B) A dynamic equilibrium exists between palmitoylated postsynaptic PSD-95 and nonpalmitoylated cytosolic PSD-95. Depalmitoylated PSD-95 diffuses into the spine and dendritic shaft. DHHC2 PAT mainly localizes in dendritic shafts on vesicles and mediates dendritic PSD-95 palmitoylation. PSD, postsynaptic density. (C) When synaptic activity is blocked, DHHC2 vesicles move into spines. This translocated DHHC2 palmitoylates spinous PSD-95; the increased postsynaptic PSD-95 thereby contributes to AMPAR homeostasis.
Mentions: Recent fluorescence recovery after photobleaching and photoconversion analyses revealed that several palmitoylated proteins such as Harvey Ras/neuroblastoma Ras (Rocks et al., 2005), Gαo (Chisari et al., 2007), and Gαq (Tsutsumi et al., 2009) rapidly shuttle between the plasma membrane and the Golgi apparatus. This constitutive shuttling comprises four steps: (1) palmitoylation by the Golgi-resident DHHC proteins, (2) trafficking to the plasma membrane, (3) depalmitoylation by a putative PPT and rapid cytosolic diffusion, and (4) transient trapping at the Golgi for repalmitoylation (Fig. 8 A; Rocks et al., 2006; Tsutsumi et al., 2009). In neurons, where the Golgi apparatus is segregated from the axon and dendrites, we suggest that Golgi-localized DHHC3 mediates the constitutive palmitoylation of PSD-95 at the cell body. In dendrites, PSD-95 depalmitoylated at the postsynaptic membrane diffuses from dendritic spine to shaft, is repalmitoylated on DHHC2-positive vesicles, and is redirected to postsynaptic membranes (Fig. 8 B). When synaptic activity is blocked, DHHC2 vesicles translocate from dendritic shafts to sites near the postsynaptic membrane. This allows DHHC2 to repalmitoylate PSD-95 in the spine (Fig. 8 C). Thus, mobile DHHC2 induces a local increase of PSD-95 palmitoylation, which leads to AMPAR recruitment. We propose that extracellular signals translocate specific DHHC PATs and create a new route for substrate shuttling between loci of palmitoylation and depalmitoylation, leading to efficient and precise substrate targeting. Such a compartmentalized regulatory mechanism of DHHC PATs may contribute to spatiotemporal regulation of signaling molecules in polarized neurons, epithelial cells, and migrating cells.

Bottom Line: We found that blocking synaptic activity rapidly induces PSD-95 palmitoylation and mediates synaptic clustering of PSD-95 and associated AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-type glutamate receptors.Upon activity blockade, DHHC2 translocates to the postsynaptic density to transduce this effect.These data demonstrate that individual DHHC members are differentially regulated and that dynamic recruitment of protein palmitoylation machinery enables compartmentalized regulation of protein trafficking in response to extracellular signals.

View Article: PubMed Central - PubMed

Affiliation: Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.

ABSTRACT
Protein palmitoylation is the most common posttranslational lipid modification; its reversibility mediates protein shuttling between intracellular compartments. A large family of DHHC (Asp-His-His-Cys) proteins has emerged as protein palmitoyl acyltransferases (PATs). However, mechanisms that regulate these PATs in a physiological context remain unknown. In this study, we efficiently monitored the dynamic palmitate cycling on synaptic scaffold PSD-95. We found that blocking synaptic activity rapidly induces PSD-95 palmitoylation and mediates synaptic clustering of PSD-95 and associated AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-type glutamate receptors. A dendritically localized DHHC2 but not the Golgi-resident DHHC3 mediates this activity-sensitive palmitoylation. Upon activity blockade, DHHC2 translocates to the postsynaptic density to transduce this effect. These data demonstrate that individual DHHC members are differentially regulated and that dynamic recruitment of protein palmitoylation machinery enables compartmentalized regulation of protein trafficking in response to extracellular signals.

Show MeSH
Related in: MedlinePlus