The Group 3 LIM domain protein paxillin potentiates androgen receptor transactivation in prostate cancer cell lines.
Paxillin, a member of the group 3 subfamily of LIM domain proteins, is localized within focal adhesions and participates in a number of signal transduction pathways mobilized upon activation of cell surface receptors. In recent years, a number of group 3 LIM domain proteins have been found to also localize within the nucleus and exert direct effects on transcription. We show here that paxillin is present within nuclei and can target the nuclear matrix of CV-1 cells, cultured prostate cancer cell lines, and human prostate tissue. The increased targeting of androgen receptor to the nuclear matrix upon overexpression of paxillin may be brought about by direct interactions between paxillin and the receptor, which were detected in vitro. Paxillin functions as a coactivator for androgen receptor and glucocorticoid receptor, but not estrogen receptor alpha, similar to its close relative Hic-5/ARA55. Both paxillin and Hic-5/ARA55 use their COOH-terminal LIM domain to interact with steroid receptors. However, paxillin is distinguished from Hic-5/ARA55 by both the location of its receptor coactivation domain (i.e., COOH-terminal LIM domain) and by the dominant-negative activity of its NH(2)-terminal domain. Thus, highly related group 3 LIM domain proteins may use distinct mechanisms to modulate steroid hormone receptor transactivation.
Kasai
Masaaki
M
Department of Pharmacology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
Guerrero-Santoro
Jennifer
J
Friedman
Robert
R
Leman
Eddy S
ES
Getzenberg
Robert H
RH
DeFranco
Donald B
DB
D003598:Cytoskeletal Proteins / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D008297:Male; D015530:Nuclear Matrix / Q000737:chemistry; D051419:Paxillin; D010750:Phosphoproteins / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D011944:Receptors, Androgen / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D003598:Cytoskeletal Proteins; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; D011944:Receptors, Androgen; D011965:Receptors, Glucocorticoid