Protein-protein interactions mapped between septin complex components. (A and H) Models of S. pombe septin interactions. (B) The PJ69-4A strain was transformed with pGBT9 or pGBT9spn3, and pGAD424 or pGAD424 carrying spn1, spn2, or spn4, which are shown schematically. (C) β-galactosidase activity (represented in relative light units) of the stains described in B. (D) The PJ69-4A stain was transformed with pGBT9 or pGBT9spn1 and pGAD424 or pGAD424 carrying spn2, spn3, or spn4, which are shown schematically. (E) β-galactosidase activity (represented in relative light units) of the stains described in D. (F) The PJ69-4A stain was transformed with pGBT9 or pGBT9spn2 and pGAD424 or pGAD424 carrying spn4, which are shown schematically. (G) β-galactosidase activity (represented in relative light units) of the stains described in D. Asterisk indicates positive interactions.