G-Protein Coupled Receptors (GPCR) sense extracellular signals and activate different Guanine nucleotide binding proteins. Upon activation, the Guanine nucleotide-binding protein subunit alpha-12 (GNA12) can bind to the non-receptor Tyrosine-protein kinase BTK. This complex facilitates BTK activation. Subsequently, the active BTK dissociates from GNA12 to phosphorylate downstream effectors. Physiologically, BTK plays a key role in B lymphocyte development, differentiation and signalling.