Model for stathmin/OP18 binding to tubulin
AUTOR(ES)
Wallon, Gerlind
FONTE
Oxford University Press
RESUMO
Stathmin/OP18 is a regulatory phosphoprotein that controls microtubule (MT) dynamics. The protein does not have a defined three-dimensional structure, although it contains three distinct regions (an unstructured N–terminus, N: 1–44; a region with high helix propensity, H 1: 44–89; and a region with low helix propensity, H 2: 90–142). The full protein and a combination of H 1 and H 2 inhibits tubulin polymerization, while the combination of H 1 and the N–terminus is less efficient. None of the individual three regions alone are functional in this respect. However, all of them cross-link to α–tubulin, but only full-length stathmin produces high-molecular-weight products. Mass spectrometry analysis of α–tubulin–stathmin/OP18 and its truncation products shows that full-length stathmin/OP18 binds to the region around helix 10 of α–tubulin, a region that is involved in longitudinal interactions in the MT, sequestering the dimer and possibly linking two tubulin heterodimers. In the absence of the N–terminus, stathmin/OP18 binds to only one molecule of α–tubulin, at the top of the free tubulin heterodimer, preventing polymerization.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=305555Documentos Relacionados
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