Proline-rich nuclear receptor coactivator 1 (PNRC1)

Proline-rich nuclear receptor coactivator 1 (PNRC1) is a non-enzymatic, proline-rich adaptor protein that functions as a coactivator for diverse nuclear receptors, including the androgen receptor (AR), estrogen receptor alpha (ERα), estrogen-related receptors (ERRα, ERRγ), glucocorticoid receptor (GR), steroidogenic factor 1 (SF1), progesterone receptor (PR), thyroid hormone receptor (TR), retinoic acid receptor (RAR), and retinoid X receptor (RXR), primarily via its SH3-binding domain. PNRC1 interacts directly with the adapter protein Grb2, enabling it to influence signaling through the Ras/MAP-kinase pathway and suppress nuclear receptor-mediated and growth factor-triggered cell proliferation. Promoter and splicing regulation define multiple isoforms with varying capacities for nuclear receptor interaction and transcriptional potentiation. PNRC1 also acts as a tumor suppressor by recruiting the cytoplasmic DCP1α/DCP2 mRNA decapping complex into the nucleolus, inhibiting rRNA maturation and blunting proliferative signals from oncogenes such as RAS and MYC. Tumors frequently show downregulated PNRC1 expression, and its presence correlates with non-proliferative cell states, supporting its role in growth restraint and cancer biology. While PNRC1 does not possess intrinsic enzymatic activity, its effect is mediated through protein–protein interactions involving mRNA decay and ribosomal RNA processing machinery. Clinical drug interactions or documented safety concerns have not been characterized as of September 2025.

Other names

PROL2B4-2PNAS-145PRR2Proline-rich protein 2Protein B4-2proline-rich polypeptide 2proline-rich protein with nuclear targeting signal