PELP-1

PELP-1 (MNAR) is a transcriptional corepressor for nuclear receptors such as glucocorticoid receptors and a coactivator for estrogen receptors.

Activation of protein kinases
PELP-1 has been shown to bind to both estrogen receptor alpha and estrogen receptor beta. It was also reported that protein tyrosine kinases of the src family can form a complex with estrogen receptors and PELP-1 and it was reported that when bound to PELP-1 and estrogen receptor alpha the kinase activity of SRC was activated in an estrogen-sensitive manner. Mitogen-activated protein kinases ERK1 and ERK2 were found to become phosphorylated in estrogen-treated cells containing PELP-1. It was reported that the enhancement of estrogen-induced gene transcription due to PELP-1 could be blocked by protein kinase inhibitors. This suggested a model of PELP-1 function in which estrogen and PELP-1 cooperate to activate protein kinases which in turn activate gene transcription.

Histone deacetylase
When functioning as a corepressor of transcription PELP-1 recruits histone deacetylase. Estrogen has been associated with stimulation of cell proliferation and progression of cells through G1 to the S phase of the cell cycle. The retinoblastoma protein (Rb) is a regulator of G1. It was reported that PELP-1 interacts with Rb. It is not known if estrogen receptors can displace histone deacetylase from Rb.