LPA5 couples to G proteins, G[[alpha].sub.q/11], and G[[alpha].sub.12/13] (Figure 1(b)), by which [Ca.sup.2+] mobilization, inositol phosphate production, neurite retraction, and stress fiber formation are mediated [51, 52].
Additionally, in rat lung carcinoma, LPA5 is highly expressed due to unmethylation of the promoter, and cells expressing only [LPA.sub.5] showed enhanced proliferation, migration, and invasion .
Along with cancers previously described, ATXLPA axis and its signaling pathways have been studied in several other carcinomas such as melanoma, where LPA signaling suppresses antigen receptor signaling, cell activation, and proliferation in CD8 T cells that express LPA5, inhibiting immune response  and promoting tumorigenesis.
D'Hooge, "LPA5 receptor plays a role in pain sensitivity, emotional exploration and reversal learning," Genes, Brain and Behavior, vol.
Moolenaar, "LPA is a chemorepellent for B16 melanoma cells: action through the cAMP-elevating LPA5 receptor," PLoS One, vol.
They identified the LPA5 receptor as the specific receptor responsible for inhibiting the immune response.
When they transferred T cells lacking the LPA5 receptor into mice with cancer, tumor growth essentially halted.