Pim-1 Kinase Protects P-Glycoprotein from Degradation and Enables Its Glycosylation and Cell Surface Expression
- 11 May 2010
- journal article
- Published by American Society for Pharmacology & Experimental Therapeutics (ASPET) in Molecular Pharmacology
- Vol. 78 (2), 310-318
- https://doi.org/10.1124/mol.109.061713
Abstract
The oncogenic serine/threonine kinase Pim-1 phosphorylates and activates the ATP-binding cassette transporter breast cancer resistance protein (ABCG2). The ABC transporter P-glycoprotein (Pgp; ABCB1) also contains a Pim-1 phosphorylation consensus sequence, and we hypothesized that Pim-1 also regulates Pgp. Pgp is exported from the endoplasmic reticulum (ER) as a 150-kDa species that is glycosylated to 170-kDa Pgp, translocates to the cell surface, and mediates drug efflux; alternatively, 150-kDa Pgp is cleaved to a 130-kDa proteolytic product by ER proteases or undergoes ubiquitination and proteasomal degradation. Pim-1 and Pgp interaction was studied in GST pull-down and phosphorylation in in vitro kinase assays. Pim-1 knockdown and inhibition effects on Pgp expression were studied by immunoblotting and flow cytometry and on Pgp stability by immunoblotting after cycloheximide treatment. Pim-1 directly interacted with and phosphorylated Pgp in intact cells and in vitro. Pim-1 knockdown or inhibition decreased cellular and cell surface 170-kDa Pgp, in association with both transient increase in 130-kDa Pgp and increased Pgp ubiquitination and proteasomal degradation. Pim-1 inhibition also decreased expression of 150-kDa Pgp in the presence of the glycosylation inhibitor 2-deoxy-d-glucose. Finally, Pim-1 inhibition sensitized Pgp-overexpressing cells to doxorubicin. Thus, Pim-1 regulates Pgp expression by protecting 150-kDa Pgp from proteolytic and proteasomal degradation and enabling Pgp glycosylation and cell surface translocation and thus Pgp-mediated drug efflux. Pim-1 inhibitors are entering clinical trials and may provide a novel approach to abrogating drug resistance.This publication has 45 references indexed in Scilit:
- Pim kinase inhibitor, SGI-1776, induces apoptosis in chronic lymphocytic leukemia cellsBlood, 2009
- Identification and structure–activity relationships of substituted pyridones as inhibitors of Pim-1 kinaseBioorganic & Medicinal Chemistry Letters, 2007
- The oncogenic serine/threonine kinase Pim-1 directly phosphorylates and activates the G2/M specific phosphatase Cdc25CThe International Journal of Biochemistry & Cell Biology, 2006
- Structure and Substrate Specificity of the Pim-1 KinaseJournal of Biological Chemistry, 2005
- Gene Expression Profile Predicts Patient Survival of Gastric Cancer After Surgical ResectionJournal of Clinical Oncology, 2005
- Pim‐1 kinase promotes inactivation of the pro‐apoptotic Bad protein by phosphorylating it on the Ser112 gatekeeper siteFEBS Letters, 2004
- Pim serine/threonine kinases regulate the stability of Socs-1 proteinProceedings of the National Academy of Sciences of the United States of America, 2002
- Adhesion of human platelets to serum amyloid ABlood, 2002
- Phosphorylation by protein kinase C and cyclic AMP-dependent protein kinase of synthetic peptides derived from the linker region of human P-glycoproteinBiochemical Journal, 1994
- The human protooncogene product p33pim is expressed during fetal hematopoiesis and in diverse leukemias.Proceedings of the National Academy of Sciences of the United States of America, 1989