TY - JOUR
T1 - The Protein Kinase C-Related PKC-L(η) Gene Product Is Localized in the Cell Nucleus
AU - Greif, Hagar
AU - Ben-Chaim, Jacob
AU - Shimon, Tova
AU - Bechor, Edna
AU - Eldar, Hagit
AU - Livneh, Etta
PY - 1992/1/1
Y1 - 1992/1/1
N2 - The tumor promoters phorbol esters are thought to induce changes in cell growth and gene expression by direct activation of protein kinase C (PKC). However, the molecular mechanisms by which PKC molecules transduce signals into the cell nucleus are unknown. In this study, we provide evidence for a direct target for phorbol esters in the nucleus. We demonstrate that the new PKC-related family member, PKC-L, recently isolated by us, is expressed specifically in the cell nucleus. Localization of PKC-L in the cell nucleus is shown both by immunofluorescence staining and by subcellular fractionation experiments of several human cell lines, including the human epidermoid carcinoma line A431. Treatment of these cells by phorbol esters does not induce the down-regulation of PKC-L, in contrast to their effect on classical PKC family members. This is the only PKC isoenzyme described so far that resides permanently and specifically in the cell nucleus. PKC-L may function as an important link in tumor promoting, e.g., as a nuclear regulator of gene expression that changes the phosphorylation state of transcriptional components such as the AP-1 complex.
AB - The tumor promoters phorbol esters are thought to induce changes in cell growth and gene expression by direct activation of protein kinase C (PKC). However, the molecular mechanisms by which PKC molecules transduce signals into the cell nucleus are unknown. In this study, we provide evidence for a direct target for phorbol esters in the nucleus. We demonstrate that the new PKC-related family member, PKC-L, recently isolated by us, is expressed specifically in the cell nucleus. Localization of PKC-L in the cell nucleus is shown both by immunofluorescence staining and by subcellular fractionation experiments of several human cell lines, including the human epidermoid carcinoma line A431. Treatment of these cells by phorbol esters does not induce the down-regulation of PKC-L, in contrast to their effect on classical PKC family members. This is the only PKC isoenzyme described so far that resides permanently and specifically in the cell nucleus. PKC-L may function as an important link in tumor promoting, e.g., as a nuclear regulator of gene expression that changes the phosphorylation state of transcriptional components such as the AP-1 complex.
UR - http://www.scopus.com/inward/record.url?scp=0026563893&partnerID=8YFLogxK
U2 - 10.1128/MCB.12.3.1304
DO - 10.1128/MCB.12.3.1304
M3 - Article
AN - SCOPUS:0026563893
SN - 0270-7306
VL - 12
SP - 1304
EP - 1311
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
IS - 3
ER -