当前位置： SCI文献检索 > MOLECULAR AND CELLULAR BIOLOGY期刊下所有文献 > Protein kinase C-theta isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes.

Protein kinase C-theta isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes.

Abstract：

:T-lymphocyte stimulation requires activation of several protein kinases, including the major phorbol ester receptor protein kinase C (PKC), ultimately leading to induction of lymphokines, such as interleukin-2 (IL-2). The revelant PKC isoforms which are involved in the activation cascades of nuclear transcription factors involved in IL-2 production have not yet been clearly defined. We have examined the potential role of two representative PKC isoforms in the induction of the IL-2 gene, i.e., PKC-alpha and PKC-theta, the latter being expressed predominantly in hematopoietic cell lines, particularly T cells. Similar to that of PKC-alpha, PKC-theta overexpression in murine EL4 thymoma cells caused a significant increase in phorbol 12-myristate 13-acetate (PMA)-induced transcriptional activation of full-length IL-2-chloramphenicol acetyltransferase (CAT) and NF-AT-CAT but not of NF-IL2A-CAT or NF-kappaB promoter-CAT reporter gene constructs. Importantly, the critical AP-1 enhancer element was differentially modulated by these two distinct PKC isoenzymes, since only PKC-theta but not PKC-alpha overexpression resulted in an approximately 2.8-fold increase in AP-1-collagenase promoter CAT expression in comparison with the vector control. Deletion of the AP-1 enhancer site in the collagenase promoter rendered it unresponsive to PKC-theta. Expression of a constitutively active mutant PKC-theta A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-theta K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-RasS17N completely inhibited the PKC-O A148E-induced signal, PKC-O. Expression of a constitutively active mutant PKC-O A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-O K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-enRasS17N completely inhibited in the PKC-O A148E-induced signal, identifying PKC-theta as a specific constituent upstream of or parallel to Ras in the signaling cascade leading to AP transcriptional activation.

journal_name

Mol Cell Biol

journal_title

Molecular and cellular biology

authors

Baier-Bitterlich G,Uberall F,Bauer B,Fresser F,Wachter H,Grunicke H,Utermann G,Altman A,Baier G

doi

10.1128/mcb.16.4.1842

subject

Has Abstract

pub_date

1996-04-01 00:00:00

pages

1842-50

issue

eissn

0270-7306

issn

1098-5549

journal_volume

pub_type

杂志文章

在线工具

Protein kinase C-theta isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes.