Anti-Human CEBPB (Phospho-Thr235/188) polyclonal antibody

Implantation of a blastocyst in the uterus is a multistep process tightly controlled by an intricate regulatory network of interconnected ovarian, uterine, and embryonic factors. Bone morphogenetic protein (BMP) ligands and receptors are expressed in the uterus of pregnant mice, and BMP2 has been shown to be a key regulator of implantation. In this study, we investigated the roles of the BMP type 1 receptor, activin-like kinase 2 (ALK2), during mouse pregnancy by producing mice carrying a conditional ablation of Alk2 in the uterus (Alk2 cKO mice). In the absence of ALK2, embryos demonstrate delayed invasion into the uterine epithelium and stroma, and upon implantation, stromal cells fail to undergo uterine decidualization, resulting in sterility. Mechanistically, microarray analysis revealed that CCAAT/enhancer-binding protein beta (Cebpb) expression is suppressed during decidualization in Alk2 cKO females. These findings and the similar phenotypes of Cebpb cKO and Alk2 cKO mice lead to the hypothesis that BMPs act upstream of CEBPB in the stroma to regulate decidualization. To test this hypothesis, we knocked down ALK2 in human uterine stromal cells (hESC) and discovered that ablation of ALK2 alters hESC decidualization and suppresses CEBPB mRNA and protein levels. Chromatin immunoprecipitation (ChIP) analysis of decidualizing hESC confirmed that BMP signaling proteins, SMAD1/5, directly regulate expression of CEBPB by binding a distinct regulatory sequence in the 3' UTR of this gene; CEBPB, in turn, regulates the expression of progesterone receptor (PGR). Our work clarifies the conserved mechanisms through which BMPs regulate peri-implantation in rodents and primates and, for the first time, uncovers a linear pathway of BMP signaling through ALK2 to regulate CEBPB and, subsequently, PGR during decidualization.

IFNG/IFN gamma plays a critical role in driving innate and acquired defenses against infectious pathogens. The death-associated protein kinase 1 (DAPK1), originally identified as an activator of IFNG-induced cell death, controls autophagy. Previously, we have shown that transcription factor CEBPB (C/EBP-beta) regulates IFNG-induced expression of Dapk1 through a CRE/ATF motif in its enhancer. In this paper we have shown that ATF6, an ER-resident transcription factor regulates IFNG-induced Dapk1 expression through the CRE/ATF site, in association with CEBPB. IFNG-stimulated proteolytic cleavage of ATF6, and MAPK1/3 (ERK2/1)-dependent phosphorylation of CEBPB together control the expression of Dapk1. Consistent with their requirement for DAPK1 expression, IFNG fails to induce autophagy in cells lacking either Atf6 or Cebpb. More importantly, the Atf6(-/-) mice are highly susceptible to lethal bacterial infections due to a loss of autophagy. This study reported a connection between ER stress and autophagy in mediating antibacterial defenses.