Molecular insights into kinase mediated signaling pathways of chemokines and their cognate G protein coupled receptors.

Chemokines are small regulatory proteins that play a crucial role in the coordinated migration of cell populations to the site of infection/inflammation by binding to their cognate receptors. In principle, chemokine receptors, which are serpentine G protein-coupled receptors (GPCRs), mediate the series of downstream intracellular signaling events that occur inside the cells to resolve the pathogenicity. Intracellular signaling pathways regulated by the kinase protein sub-families are the center of attention for chemokine derived functional responses. Kinases potentially influence cell migration, cell growth, transcriptional activation, and other essential molecular events. The regulation and flow of the signals by the kinases are different for each physiological and pathological event and are tightly regulated by the nature and pairing of chemokine(s) with its receptor(s). For example, phosphoinositide 3-kinase (PI3K) is activated during the initial steps of the chemokine induced signaling cascade to regulate chemotaxis, transcription, and cell survival. G protein-coupled receptor kinase (GRKs) plays a crucial role in the desensitization and internalization of the chemokine receptors. The regulation of chemokine receptor is also governed by kinases like protein kinase A (PKA), protein kinase C (PKC), mitogen-activated protein kinases / extracellular signal-regulated kinases (MAPK/ERK), . It was also established that tyrosine-protein kinases (TECs) such as ITK and RLK play a significant role in chemokine signaling in T lymphocytes. On a similar note, many others like janus kinases (JAKs), Protein kinase B (PKB), PKC, etc. are also studied in chemokine mediated disease models. The present review elucidates the role of different kinases involved in the chemokine/chemokine receptor mediated signaling cascade during various pathophysiological processes.