In vivo requirement of the α-syntrophin PDZ domain for the sarcolemmal localization of nNOS and aquaporin-4

Adams, Marvin E.; Mueller, H.; Froehner, Stanley C.

doi:10.1083/jcb.200106158

Cited by 165 publications

(152 citation statements)

References 52 publications

(95 reference statements)

Supporting

Mentioning

150

Contrasting

Order By: Relevance

“…Interactions with syntrophin are not required for the association of Na V 1 with the plasma membrane (Adams et al, 2001). Our findings that syntrophin is already concentrated at the NMJ before birth and does not have the same membrane distribution as ankyrinG or Na V 1 during the first 2 weeks after birth suggests that syntrophins are unlikely to play a role in initiating Na V 1 accumulation at the NMJ.…”

Section: Stabilization Of Na V 1 Clusters At Maturing Nmjsmentioning

confidence: 68%

Voltage-Gated Sodium Channels and AnkyrinG Occupy a Different Postsynaptic Domain from Acetylcholine Receptors from an Early Stage of Neuromuscular Junction Maturation in Rats

et al. 2003

View full text Add to dashboard Cite

Spatial segregation of membrane proteins is a feature of many excitable cells. In skeletal muscle, clusters of acetylcholine receptors (AChRs) and voltage-gated sodium channels (Na V 1s) occupy distinct domains at the neuromuscular junction (NMJ). We used quantitative immunolabeling of developing rat soleus muscles to study the mechanism of ion channel segregation and Na V 1 clustering at NMJs. When Na V 1s can first be detected, at birth, they already occupy a postsynaptic domain that is distinct from that occupied by AChRs. At this time, Na V 1s are expressed only in a diffuse area that extends 50 -100 m from the immature NMJ. However, in the region of the high-density AChR cluster at NMJ itself, Na V 1s are actually present in lower density than in the immediately surrounding membrane. These distinctive features of the Na V 1 distribution at birth are closely correlated with the distribution of ankyrinG immunolabeling. This suggests that an interaction with ankyrinG plays a role in the initial segregation of Na V 1s from AChRs. Both Na V 1 and ankyrinG become clustered at the NMJ itself 1-2 weeks after birth, coincident with the formation of postsynaptic folds. Syntrophin immunolabeling codistributes with AChRs and never resembles that for Na V 1 or ankyrinG. Therefore, syntrophin is unlikely to play an important part in the initial accumulation of Na V 1 at the NMJ. These findings suggest that the segregation of Na V 1 from AChRs begins early in NMJ formation and occurs as a result of the physical exclusion of Na V 1 and ankyrinG from the region of nerve-muscle contact rather than by a process of active clustering.

show abstract

Section: Stabilization Of Na V 1 Clusters At Maturing Nmjsmentioning

confidence: 68%

Voltage-Gated Sodium Channels and AnkyrinG Occupy a Different Postsynaptic Domain from Acetylcholine Receptors from an Early Stage of Neuromuscular Junction Maturation in Rats

et al. 2003

View full text Add to dashboard Cite

show abstract

“…51 AQP4 is also associated with Kir 4.1 and with other components of DAPs, 28,48 such as a-syntrophin, which anchored AQP4 in a polarized way on the astrocytic membranes facing the vessels by interaction of its PDZ domain with the C-terminal SSV residues of AQP4. 13,52,53 Furthermore, a-syntrophin-null mice showed AQP4 reduction and redistribution and delayed K þ clearance, 13,31 suggesting that a correct link between AQP4 proteins and DAPs is necessary for an efficient K þ removal.…”

Section: Discussionmentioning

confidence: 99%

Glial dystrophin-associated proteins, laminin and agrin, are downregulated in the brain of mdx mouse

Nico

Tamma

Annese

et al. 2010

Laboratory Investigation

View full text Add to dashboard Cite

In this study, we investigated the involvement of dystrophin-associated proteins (DAPs) and their relationship with the perivascular basement membrane in the brains of mdx mice and controls at the age of 2 months. We analyzed (1) the expression of glial DAPs a-b-dystroglycan (DG), a-syntrophin, aquaporin-4 (AQP4) water channel, Kir 4.1 and dystrophin isoform (Dp71) by immunocytochemistry, laser confocal microscopy, immunogold electron microscopy, immunoblotting and RT-PCR; (2) the ultrastructure of the basement membrane and expression of laminin and agrin; and (3) the dual immunofluorescence colocalization of AQP4/a-b-DG, and of Kir 4.1/agrin. The following results were observed in mdx brain as compared with controls: (1) a significant reduction in protein content and mRNA expression of DAPs; (2) ultrastructurally, a thickened and discontinuous appearance of the basement membrane and a significant reduction in laminin and agrin; and (3) a molecular rearrangment of a-b-DG, coupled with a parallel loss of agrin and Kir 4.1 on basement membrane and glial endfeet. These data indicate that in mdx brain the deficiency in dystrophin and dystrophin isoform (Dp71) is coupled with a reduction of DAP components, coupled with an altered anchoring to the basement membrane. The blood-brain barrier (BBB) controls the selective exchanges between blood and neuropil by specific molecular and structural features of its vascular and perivascular components, including endothelial cells, pericytes, glial endfeet and basement membrane. 1-3 Glial cells have a key role in the control of BBB development and integrity. They express in a polarized way, on their perivascular endfeet, carrier membranes and channel proteins, including aquaporin-4 (AQP4) water channel and potassium channel Kir 4.1, which are responsible for the water flow rate and spatial K þ buffering control. [4][5][6][7][8][9] In the retina, AQP4 colocalizes with Kir 4.1, 9-11 suggesting a tight cooperation between the water flux and K þ siphoning generated by neuronal activity at the BBB interfaces. Moreover, AQP4 and Kir 4.1 rearrangement has been described in BBB alterations, coupled with cytotoxic edema and K þ -delayed buffering capacity. 12,13 AQP4 has a crucial role in the regulation of the interactions occurring between endothelial and glial cells and between glial cells and the extracellular matrix components. AQP4 is a component of the orthogonal aggregate particles (OAPs), demonstrated by freeze fracturing on the ependimoglial membrane and perivascular glial endfeet, 14 the development of which occurs in parallel with AQP4 glial endfeet expression and BBB maturation. 7 Moreover, OAPs contain AQP4 associated with Kir 4.1 12 and their polarized distribution on the glial endfeet seems to be dependent by the presence of the perivascular basement membrane. 15 AQP4 controls BBB functioning, modifying

show abstract

“…The molecular composition of the DGC differs between muscle sarcolemma, neuromuscular junction, brain and retina, and astrocytes [91,92], where, for instance, the DGC is involved in proper membrane targeting of aquaporin 4 at end-feet in contact with brain blood vessels [93,94].…”

Section: The Dystrophin-glycoprotein Complexmentioning

confidence: 99%

Molecular and functional heterogeneity of GABAergic synapses

Fritschy

Panzanelli

Tyagarajan

2012

Cell. Mol. Life Sci.

View full text Add to dashboard Cite

Knowledge of the functional organization of the GABAergic system, the main inhibitory neurotransmitter system, in the CNS has increased remarkably in recent years. In particular, substantial progress has been made in elucidating the molecular mechanisms underlying the formation and plasticity of GABAergic synapses. Evidence available ascribes a key role to the cytoplasmic protein gephyrin to form a postsynaptic scaffold anchoring GABA(A) receptors along with other transmembrane proteins and signaling molecules in the postsynaptic density. However, the mechanisms of gephyrin scaffolding remain elusive, notably because gephyrin can auto-aggregate spontaneously and lacks PDZ protein interaction domains found in a majority of scaffolding proteins. In addition, the structural diversity of GABA(A) receptors, which are pentameric channels encoded by a large family of subunits, has been largely overlooked in these studies. Finally, the role of the dystrophin-glycoprotein complex, present in a subset of GABAergic synapses in cortical structures, remains ill-defined. In this review, we discuss recent results derived mainly from the analysis of mutant mice lacking a specific GABA(A) receptor subtype or a core protein of the GABAergic postsynaptic density (neuroligin-2, collybistin), highlighting the molecular diversity of GABAergic synapses and its relevance for brain plasticity and function. In addition, we discuss the contribution of the dystrophin-glycoprotein complex to the molecular and functional heterogeneity of GABAergic synapses. AbstractKnowledge of the functional organization of the GABAergic system, the main inhibitory neurotransmitter system, in the CNS has increased remarkably in recent years. In particular, substantial progress has been made in elucidating the molecular mechanisms underlying formation and plasticity of GABAergic synapses. Evidence available ascribes a key role to the cytoplasmic protein gephyrin to form a postsynaptic scaffold anchoring GABA A receptors along with other transmembrane proteins and signaling molecules in the postsynaptic density. However, the mechanisms of gephyrin scaffolding remain elusive, notably because gephyrin can auto-aggregate spontaneously and lacks PDZ protein interaction domains found in a majority of scaffolding proteins. In addition, the structural diversity of GABA A receptors, which are pentameric channels encoded by a large family of subunits, has been largely overlooked in these studies. Finally, the role of the dystrophin-glycoprotein complex, present in a subset of GABAergic synapses in cortical structures, remains ill-defined. In this review, we discuss recent results derived mainly from the analysis of mutant mice lacking a specific GABA A receptor subtype or a core protein of the GABAergic postsynaptic density (neuroligin-2, collybistin), highlighting the molecular diversity of GABAergic synapses and its relevance for brain plasticity and function. In addition, we discuss the contribution of the dystrophinglycoprotein complex to the molecular ...

show abstract

In vivo requirement of the α-syntrophin PDZ domain for the sarcolemmal localization of nNOS and aquaporin-4

Cited by 165 publications

References 52 publications

Voltage-Gated Sodium Channels and AnkyrinG Occupy a Different Postsynaptic Domain from Acetylcholine Receptors from an Early Stage of Neuromuscular Junction Maturation in Rats

Voltage-Gated Sodium Channels and AnkyrinG Occupy a Different Postsynaptic Domain from Acetylcholine Receptors from an Early Stage of Neuromuscular Junction Maturation in Rats

Glial dystrophin-associated proteins, laminin and agrin, are downregulated in the brain of mdx mouse

Molecular and functional heterogeneity of GABAergic synapses

Contact Info

Product

Resources

About