Regulation of the LPA2 receptor signaling through the carboxyl-terminal tail-mediated protein-protein interactions.

While it is well known that lysophosphatidic acid (LPA) mediates diverse physiological and pathophysiological responses through the activation of G protein-coupled LPA receptors, the specificity and molecular mechanisms by which different LPA receptors mediate these biological responses remain largely unknown. Recent identification of several PDZ proteins and zinc finger proteins that interact with the carboxyl-terminal tail of the LPA2 receptor provides a considerable progress towards the understanding of the mechanisms how the LPA2 receptor specifically mediates LPA signaling pathways. These findings have led to the proposal that there are at least two distinct protein interaction motifs present in the carboxyl-terminus of the LPA2 receptor. Together, these data provide a new concept that the efficiency and specificity of the LPA2 receptor-mediated signal transduction can be achieved through the cross-regulation between the classical G protein-activated signaling cascades and the interacting partner-mediated signaling pathways.