GNA13 and lymphoma: Another pathway frequently mutated in GC-derived lymphomas is the GC homing pathway involving S1PR2 and GNA13. The guanine nucleotide binding protein GNA13 (encoding Gα13), is a signaling mediator downstream of transmembrane G-protein-coupled receptors sphingosine-1-phosphate receptor-2 (S1PR2), that confines B cells in the GC and promotes growth regulation by suppressing both Akt and cell migration (110).