8.A.202.  The Proline-rich Receptor (PrR) Family 

The proline-rich protein 7/transmembrane adapter protein 3 (Prr7) down-regulation in dendrites of rat hippocampal neurons is necessary for homeostatic synaptic depression (HSD) in excitatory neuronsinduced by chronic increase in network activity resulting from a blockade of inhibitory synaptic transmission by picrotoxin (PTX) (Inouye et al. 2022).  The small regulatory RNAs, miR-329-3p and miR-495-3p inhibit Prr7 mRNA translation and are required for HSD. Prr7 knockdown reduces expression of the synaptic scaffolding protein SPAR, which is rescued by pharmacological inhibition of CDK5, indicating a role of the Prr7 protein in the maintenance of excitatory synapses via protection of SPAR from degradation. Thus, a novel HSD mechanism is revealed in which chronic activity leads to miR-329- and miR-495-mediated Prr7 reduction, upstream of the CDK5-SPAR pathway.


 

References:

Hrdinka, M., P. Dráber, O. Stepánek, T. Ormsby, P. Otáhal, P. Angelisová, T. Brdicka, J. Paces, V. Horejsí, and K. Drbal. (2011). PRR7 is a transmembrane adaptor protein expressed in activated T cells involved in regulation of T cell receptor signaling and apoptosis. J. Biol. Chem. 286: 19617-19629.
Inouye, M.O., D. Colameo, I. Ammann, J. Winterer, and G. Schratt. (2022). miR-329- and miR-495-mediated Prr7 down-regulation is required for homeostatic synaptic depression in rat hippocampal neurons. Life Sci Alliance 5:.
Examples:

TC#NameOrganismal TypeExample
8.A.202.1.1

Proline-rich protein 7/transmembrane adapter protein 3 (Prr7) is down-regulated in dendrites of rat hippocampal neurons, and this is necessary for homeostatic synaptic depression (HSD) induced by a chronic increase in network activity resulting from a blockade of inhibitory synaptic transmission by picrotoxin (PTX) (Inouye et al. 2022). Two activity-regulated miRNAs, miR-329-3p and miR-495-3p, inhibit Prr7 mRNA translation and are required for HSD. Prr7 knockdown reduces expression of the synaptic scaffolding protein SPAR, which is rescued by pharmacological inhibition of CDK5, indicating a role of the Prr7 protein in the maintenance of excitatory synapses via protection of SPAR from degradation. Thus, an HSD mechanism is established in which chronic activity leads to miR-329- and miR-495-mediated Prr7 reduction upstream of the CDK5-SPAR pathway (Hrdinka et al. 2011).

PRR7 of Homo sapiens

 
8.A.202.1.2

Pollen-specific leucine-rich repeat extensin-like protein 1 isoform X2 of 273 aas and 0 TMSs.

Plr1, isoform X2 of Plectropomus leopardus

 
8.A.202.1.3

Proline-rich protein 7 isoform X1, Prr7 -X1, of 293 aas and 1 N-terminal TMS.

Prr7-X1 of Silurus meridionalis

 
8.A.202.1.4

Proline-rich protein 7, Prr7, of 292 aas and 1 N-terminal TMS.

Prr7 of Clupea harengus (Atlantic herring)
 
8.A.202.1.5
Uncharacterized protein of 193 aas and 1 N-terminal TMS.
UP of Takifugu flavidus (sansaifugu)