PTTG is a secretory protein in human pituitary adenomas and in mouse pituitary tumor cell lines.
The pituitary tumor-transforming gene (PTTG) is a homolog of yeast Securin, which arrests the activation of Separin to induce sister chromatid separation in the transition from metaphase to anaphase. Pituitary tumor-transforming gene is also known to induce angiogenesis during pituitary tumorigenesis. It has not been clarified whether PTTG functions as a cytoplasmic or a nuclear protein. Our immunohistochemical study indicated that PTTG is localized in the cytoplasm of pituitary tumor cells. In the present study, confocal laser scanning microscopy (CLSM) analysis of human pituitary adenomas and immunoelectron microscopy of the mouse pituitary cell line, AtT-20, demonstrated the localization of PTTG in the Golgi apparatus and vesicles. Secreted PTTG was detected by immunoblotting from culture medium of mouse pituitary tumor cell lines. Our results suggested that PTTG is a secretory protein produced by pituitary tumor cells. In addition, PTTG may exert autocrine and/or paracrine functions as a newly proposed important pathway for the action of PTTG.
Minematsu
Takeo
T
Department of Pathology, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa 259-1193, Japan.
Egashira
Noboru
N
Kajiya
Hanako
H
Takei
Mao
M
Takekoshi
Susumu
S
Itoh
Yoshiko
Y
Tsukamoto
Hideo
H
Itoh
Johbu
J
Sanno
Naoko
N
Teramoto
Akira
A
Osamura
Robert Yoshiyuki
RY
D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D045744:Cell Line, Tumor / Q000378:metabolism* / Q000473:pathology; D015870:Gene Expression; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007124:Immunoenzyme Techniques; D051379:Mice; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D064249:Securin
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D064249:Securin; C578002:pituitary tumor-transforming protein 1, human