6533b7d0fe1ef96bd125b8cb

RESEARCH PRODUCT

The Functional Role of the Second NPXY Motif of the LRP1 β-Chain in Tissue-type Plasminogen Activator-mediated Activation of N-Methyl-D-aspartate Receptors

Sascha WeggenClaus U. PietrzikAnne M. MartinVolkmar LessmannElaine WaldronSebastian JaegerHeiko J. LuhmannAnton RoebroekChristoph R.w. KuhlmannAlexander LaatschSvenja Trossbach

subject

Cell signalingAmino Acid MotifsPDZ domainIntracellular SpaceBiologyReceptors N-Methyl-D-AspartateBiochemistryProtein Structure SecondaryCell LineRats Sprague-DawleyMiceStructure-Activity RelationshipAnimalsHumansAmino Acid SequencePhosphorylationRNA Small InterferingReceptorProtein kinase AMolecular BiologyMitogen-Activated Protein Kinase 1NeuronsMitogen-Activated Protein Kinase 3Activator (genetics)Intracellular Signaling Peptides and ProteinsMembrane ProteinsReceptor Cross-TalkCell BiologyLRP1RatsCell biologyEnzyme ActivationBiochemistryTissue Plasminogen ActivatorDisks Large Homolog 4 ProteinCalciumDisks Large Homolog 4 ProteinGuanylate KinasesPlasminogen activatorLow Density Lipoprotein Receptor-Related Protein-1PlasmidsSignal Transduction

description

The low density lipoprotein receptor-related protein 1 (LRP1) emerges to play fundamental roles in cellular signaling pathways in the brain. One of its prominent ligands is the serine proteinase tissue-type plasminogen activator (tPA), which has been shown to act as a key activator of neuronal mitogen-activated protein kinase pathways via the N-methyl-D-aspartate (NMDA) receptor. However, here we set out to examine whether LRP1 and the NMDA receptor might eventually act in a combined fashion to mediate tPA downstream signaling. By blocking tPA from binding to LRP1 using the receptor-associated protein, we were able to completely inhibit NMDA receptor activation. Additionally, inhibition of NMDA receptor calcium influx with MK-801 resulted in dramatic reduction of tPA-mediated downstream signaling. This indicates a functional interaction between the two receptors, since both experimental approaches resulted in strongly reduced calcium influx and Erk1/2 phosphorylation. Additionally, we were able to inhibit Erk1/2 activation by competing for the LRP1 C-terminal binding motif with a truncated PSD95 construct resembling its PDZ III domain. Furthermore, we identified the distal NPXY amino acid motif in the C terminus of LRP1 as the crucial element for LRP1-NMDA receptor interaction via the adaptor protein PSD95. These results provide new insights into the mechanism of a tPA-induced, LRP1-mediated gating mechanism for NMDA receptors.

yearjournalcountryeditionlanguage
2008-03-07Journal of Biological Chemistry
https://doi.org/10.1074/jbc.m707607200