A) XMAP215/Dis1 molecules wrap around soluble tubulin dimers with their TOG domains to form globular complexes. Models for tubulin binding are shown on the left, and electron microscopy images are shown on the right (Stu2 or XMAP215 alone, above; tubulin complex, below). Yeast Stu2 is a homodimer with two sets of TOG domains that wrap around a single tubulin dimer, while Xenopus XMAP215 is a monomer with two internal “halves” each consisting of two TOG domains that interact with a single tubulin dimer. EM images of XMAP215 and Stu2 are reproduced with permission from [12, 14]. White Arrows denote the open conformation of XMAP215 and Stu2 molecules
B) S.pombe CLASP, Cls1 is a homodimer that wrap around soluble tubulin dimers with two sets of TOGL domains. Model for Cls1 dimer binding to the tubulin dimer is shown on the left; electron microscopy images are shown on the right (Cls1 alone, above; cls1-tubulin complex, below). EM of Cls1 were reproduced with permission from [15] White Arrows denote the open conformation of XMAP215 and Stu2 molecules