NONNEURONAL ISOFORMS OF STOP PROTEIN ARE RESPONSIBLE FOR MICROTUBULE COLD STABILITY IN MAMMALIAN FIBROBLASTS

Citation
E. Denarier et al., NONNEURONAL ISOFORMS OF STOP PROTEIN ARE RESPONSIBLE FOR MICROTUBULE COLD STABILITY IN MAMMALIAN FIBROBLASTS, Proceedings of the National Academy of Sciences of the United Statesof America, 95(11), 1998, pp. 6055-6060
Citations number
38
Categorie Soggetti
Multidisciplinary Sciences
ISSN journal
00278424
Volume
95
Issue
11
Year of publication
1998
Pages
6055 - 6060
Database
ISI
SICI code
0027-8424(1998)95:11<6055:NIOSPA>2.0.ZU;2-Y
Abstract
A number of cycling mammalian cells, such as NIH 3T3, contain abundant subsets of cold-stable microtubules, The origin of such microtubule s tabilization in nonneuronal cells is unknown, We have previously descr ibed a neuronal protein, stable tubule-only polypeptide (STOP), that b inds to microtubules and induces cold stability. We find that NIH 3T3 fibroblasts contain a major 42-kDa isoform of STOP (fibroblastic STOP, F-STOP), F-STOP contains the central repeats characteristic of brain STOP but shows extensive deletions of N- and C-terminal protein domain s that are present in brain STOP. These deletions arise from differenc es in STOP RNA splicing, Despite such deletions, F-STOP has full micro tubule stabilizing activity. F-STOP accumulates on cold-stable microtu bules of interphase arrays and is present on stable microtubules withi n the mitotic spindle of NIH 3T3 cells, STOP inhibition by microinject ion of affinity-purified STOP central repeat antibodies into NIH 3T3 c ells abolishes both interphase and spindle microtubule cold stability. Similar results were obtained with Rat2 cells. These results show tha t STOP proteins have nonneuronal isoforms that are responsible for the microtubule cold stability observed in mammalian fibroblasts.