The receptor tyrosine phosphatase (RTP) family is a relatively small group of cell-surface proteins with a simple intracellular enzymatic function in the dephosphorylation of phosphotyrosine proteins. There is less known about the endogenous extracellular ligands which regulate RTP activities in physiological conditions, although some RTPs are activated by cell-surface proteins thought to be expressed on neighbouring cells.
This report  from the National Institute on Drug Abuse in the USA focusses on the role of RTP type D on reward associated with cocaine administration. They identify that RTP type D heterozygous knockout mice exhibit lower reward responses to cocaine, and that a novel small molecule that appears to target the enzymatic function of RTP type D is able to reduce cocaine-induced place preference and self-administration in wild type, but not heterozygous knockout mice.
Comments by Steve Alexander (@mqzspa)
(1) Uhl GR et al. (2018). β-Subunit of the voltage-gated Ca2+ channel Cav1.2 drives signaling to the nucleus via H-Ras. Proc Natl Acad Sci USA, pii: 201720446. doi: 10.1073/pnas.1720446115. [Epub ahead of print] [PMID: 30348770]