Polarized targeting of DNER into dendritic plasma membrane in hippocampal neurons depends on endocytosis

Abstract

J. Neurochem. (2010) 113, 1598–1610. Abstract The targeting of membrane proteins into axons and dendrites is of critical importance for directional signal transmission within specific neural circuits. Many dendritic proteins have been shown to reach the somatodendritic membrane based on selective sorting and transport of carrier vesicles. Using rat hippocampal neurons in culture, we investigated the trafficking pathways of Delta/Notch‐like EGF‐related receptor (DNER), a transmembrane Notch ligand which is specifically expressed in CNS dendrites. Mutations in the cytoplasmic domain of DNER that abolished somatodendritic localization also increased its surface expression. Furthermore, inhibition of endocytosis resulted in disruption of the somatodendritic localization of DNER, indicating that the somatodendritic targeting of DNER is dependent on endocytosis. The DNER cytoplasmic domain binds to a clathrin adaptor protein complex‐2 via a proximal tyrosine motif and a 40 amino acid stretch in the mid‐domain, but not by the C‐terminal tail. Molecular and pharmacological inhibition revealed that the surface expression of DNER is regulated by clathrin‐dependent and ‐independent endocytosis. In contrast, the somatodendritic targeting of DNER is predominantly regulated by clathrin‐ and adaptor protein complex‐2‐independent endocytosis via the C‐terminal tail of DNER. Our data suggest that clathrin‐independent endocytosis is critical for the polarized targeting of somatodendritic proteins.

Endosomal system genetics and autism spectrum disorders: A literature review

“…One example is the Delta/Notch-like EGF related receptor. Delta/Notch-like EGF receptor is specifically found in dendrites and is important for the development and functionality of the nervous system and it has been shown to be controlled by the process of clathrin-mediated endocytosis (Kurisu et al, 2010). …”

Mechanisms of polarized membrane trafficking in neurons — Focusing in on endosomes

“…Endocytosis might also be important for somatodendritic targeting of some receptors. For example, DNER, a transmembrane Notch ligand, was shown to require endocytosis for accurate somatodendritic targeting (Kurisu et al, 2010). It remains to be determined if other somatodendritic proteins might also show impaired ability to localize to the somatodendritic domain when endocytosis is impaired.…”

Insights into Serotonin Receptor Trafficking

“…These 5-HT 1A R constitutive endocytosis/recycling events could be involved in "retargeting" of receptors to specific postsynaptic sites so as to modulate receptor function as it has been shown for the Delta/Notch-like EGF-related receptor (DNER). 37 Indeed, this receptor exhibits a somatodendritic localization in hippocampal neurons, with only a small proportion found on the cell surface in a punctate pattern, while the majority resides in intracellular organelles. Disruption of endocytosis induces an increase in cell surface expression of DNER, resulting in a rather uniformly distribution of the receptor in the axon and dendrites, then broadly and evenly localized on the cell surface.…”

“…The somatodendritic targeting of DNER requires a clathrin-independent endocytosis, not implicated in the somatodendritic targeting of other polarized receptors. 37 Agonist-dependent 5-HT 1A R internalization does exist in neuronal cultures but depends on agonist efficacy and neuronal phenotype. Acute stimulation by full agonists only triggers internalization of 5-HT 1A R in serotonergic raphe neurons but not in hippocampal neurons.…”