|Title:||Association of heterotrimeric GTP binding regulatory protein (Go) with mitosis||Authors:||WU, HAN-CHUNG
|Issue Date:||1994||Journal Volume:||v.71||Journal Issue:||n.2||Start page/Pages:||175-181||Source:||LABORATORY INVESTIGATION||Abstract:||
The heterotrimeric GTP-binding regulatory proteins (or Gproteins) play an important role in regulation of mimbrane signal transduction. Previously we have identified the β- subunit of G proteins (GS) to be closely associated with mitotic spindles. In the present study, we have conducted experiments to examine whether the Gα subunit is also associated with mitotic spindles. We prepared polyclonal antibodies against synthetic oligopeptides from different Gα subunits and used them to localize Gα in a nasopharyngeal carcinoma cell line by both immunohistochemistry and immunoelectron microscopy, and to see whether any specific Gα subunit was present in the mitotic spindle region. Subsequently, we used a colocalization method to identify the overlapping distributions of specific Gα subunits andβ-tubulin. To be sure that the findings represented a general phenomenon, several other cell types were also examined. To identify whether the Gα subunit in the mitotic spindle was present in a heterotrimeric form, we performed ADP ribosylation experiments.(a)Only Goα subunit but not Giα or Gsα was localized in the mitotic spindle. (b)Goα was colocalized with β-tubulin in the mitotic spindle.(c)The precise site of localization of Goα on spindle microtubules was confirmed by immunoultrastructural study. (d)The association of Goα with the mitotic spindle could be found in both human and animal cell types. (e) The mitotic spindle preparation could be ADP ribosylated in the presence of pertussis toxin. The heterotrimeric Go protein is shown to be closely associated with the mitotic spindle. This finding suggests that Go protein may play some role in the regulation of mitotic spindles in addition to its regulation of signal transduction in neuronal cell membranes.#0439#
|Appears in Collections:||口腔生物科學研究所|
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