Neto1 associates with the NMDA receptor/amyloid precursor protein complex

Abstract

Neuropilin tolloid-like 1 (Neto1), is a CUB domain-containing transmembrane protein that was recently identified as a novel component of the NMDA receptor complex. Here, we have investigated the possible association of Neto1 with the amyloid precursor protein (APP)695/GluN1/GluN2A and APP695/ GluN1/GluN2B NMDA receptor trafficking complexes that we have previously identified. Neto1HA was shown to co-immu- Neuropilin tolloid-like 1 (Neto1) and Neuropilin tolloid-like 2 (Neto2) are complement C1r/C1s, Uegf, Bmp1 (CUB) domain-containing transmembrane proteins that were recently identified as novel components of glutamatergic neurotransmitter receptor complexes. Neto1 and Neto2 have both been described as auxiliary subunits of kainate receptors since they were shown to alter the trafficking, channel kinetics and pharmacology of this glutamate receptor subtype in a subunitdependent manner ( Abbreviations used: AMPA, 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propanoic acid; APP, amyloid precursor protein; CUB, complement C1r/C1s, Uegf, Bmp1; ELISA, enzyme linked immunoadsorbent assay; GluN1, GluN2A, GluN2B, NMDA receptor NR1 subunit, NR2A subunit, NR2B subunit; Neto1, neuropilin tolloid-like 1; NMDA, N-methyl-D-aspartate; PSD-95, post-synaptic density 95; SAP102, synapse associated protein 102. 554

A structural biology perspective on NMDA receptor pharmacology and function

“…Since the CTD is predicted to be unstructured [58], alternative approaches such as single molecule FRET could be relevant to solving the issue of how interactions at this domain alter channel activity [57]. Other molecular factors that could regulate NMDAR activities are transmembrane auxiliary proteins; whether or not such auxiliary proteins exist for NMDARs continues to be an intriguing question, although NETO1 [59], EphB [60], and the zinc transporter ZNT1 [61] have been suggested to at least indirectly affect NMDAR activity. Ultimately, the combination of structural and dynamics research into NMDAR function, together with advances in neuropharmacology, will not only fill the current knowledge gaps in the field, but will also be the driving force for the design of compounds with better affinity, potency, and selectivity.…”

Advances in the pharmacology of lGICs auxiliary subunits

“…The NMDA receptor is a tetramer and it has been described in association with several proteins, including scaffolding, peptide and signaling There is controversy whether NMDARs posses or not auxiliary subunits, as there are several candidate proteins, but not obvious evidence. For example, the NETO1 protein has been structurally associated to NMDARs complex [85].…”

Are Neto1 and APP auxiliary subunits of NMDA receptors?

“…While Neto1 does not co‐immunoprecipitate with APP directly, Neto1, APP, GluN1/GluN2A or GluN1/GluN2B are all part of the same protein complex (Cousins et al . ) (Fig. ).…”

“…The results indicate that Neto1 co‐immunoprecipitates with heteromeric NMDARs via GluN2A or GluN2B subunits (Cousins et al . ). The previously reported contradictory observations (Ng et al .…”

“…In this issue, Cousins et al . (), provide new insights into the role of Neto1 as NMDAR‐associated protein. The investigations also included the amyloid precursor protein (APP), which also appears to meet some of the criteria for NMDAR auxiliary subunit (Cousins et al .…”