The crosstalk between the free fatty acid receptor FFA4 and the lysophosphatidic acid receptor LPA1 seems to be of pathophysiological importance. We explored this crosstalk employing co-expression of fluorescent protein-tagged receptors. FFA4 activation induces functional desensitization of LPA1 receptors and phosphorylation of both receptors. LPA1 activation induces phosphorylation of LPA1 , but not of FFA4, and induces internalization of both receptors into heterogeneous types of vesicles. Docosahexaenoic acid (DHA) induces internalization of FFA4 but not of LPA1 . Fatty acid-induced FFA4-LPA1 interaction was observed using Förster resonance energy transfer and co-immunoprecipitation. Such interaction took place after desensitization was already established. Data indicate that FFA4 activation induces LPA1 desensitization in an internalization-independent process and that complex cellular processes participate in the crosstalk of these receptors.
Keywords: FRET; FFA4 receptor; LPA1 desensitization; receptor crosstalk; receptor-receptor interaction.
© 2018 Federation of European Biochemical Societies.