Prolactin (PRL) is a single peptide chain composed of 199 amino acid residues, with 3 disulfide bonds, showing strong homology to growth hormone (GH). Prolactin is secreted by the anterior pituitary gland and plays a wide range of roles in osmoregulation, corpus luteum formation, mammary gland development, lactobacillus growth, lactation, and crop milk production. In birds, PRL is widely considered crucial for initiating and sustaining reproduction. The actions of PRL hormone are mediated by its receptor (PRLR), which plays a key role in PRL signal transduction cascades.Prolactin receptor (PRLR) is encoded by the PRLR gene located on human chromosome 5p13-14, belonging to the class I cytokine receptor family. PRLR is a membrane-bound protein of the cytokine receptor superfamily. PRLR can also bind to growth hormone (GH) and human placental lactogen (hPL), with important roles in mammary alveolar development during pregnancy and lactation.The classical way of transmitting prolactin signals in the mammary gland is through the Jak2-STATs pathway. Upon binding to its receptor, prolactin leads to receptor dimerization and activation of Jak2 through phosphorylation. Jak2 then phosphorylates STATs, leading to dimerization and translocation of STATs to the cell nucleus, where they activate target genes.This is a luciferase-reporter cell line based on the Jak2-STATs signaling pathway. Upon binding of prolactin to its receptor, dimerization of the receptor and activation of Jak2 by phosphorylation occur. Jak2 further phosphorylates STATs, leading to their nuclear translocation and activation of luciferase expression. Luciferase readings reflect the activation effect of the signaling pathway, making it suitable for evaluating the in vitro effects of PRLR-related drugs.
