PLAC1 is essential for FGF7/FGFRIIIb-induced Akt-mediated cancer cell proliferation.

PLAC1 (placenta enriched 1) is a mammalian trophoblast-specific protein. Aberrant expression of PLAC1 is observed in various human cancers, where it is involved in the motility, migration, and invasion of tumor cells, which are associated with the phosphoinositide 3-kinase (PI3K)/AKT pathway. We previously demonstrated that AKT activation mediates the downstream effects of PLAC1; however, the molecular mechanisms of PLAC1-induced AKT-mediated tumor-related processes are unclear.

Dissociation of VE-PTP from VE-cadherin is required for leukocyte extravasation and for VEGF-induced vascular permeability in vivo.

We have recently shown that vascular endothelial protein tyrosine phosphatase (VE-PTP), an endothelial membrane protein, associates with VE-cadherin and is required for optimal VE-cadherin function and endothelial cell contact integrity. The dissociation of VE-PTP from VE-cadherin is triggered by vascular endothelial growth factor (VEGF) and by the binding of leukocytes to endothelial cells in vitro, suggesting that this dissociation is a prerequisite for the destabilization of endothelial cell contacts. Here, we show that VE-cadherin/VE-PTP dissociation also occurs in vivo in response to LPS stimulation of the lung or systemic VEGF stimulation.

VE-PTP controls blood vessel development by balancing Tie-2 activity.

Vascular endothelial protein tyrosine phosphatase (VE-PTP) is an endothelial-specific receptor-type tyrosine phosphatase that associates with Tie-2 and VE-cadherin. VE-PTP gene disruption leads to embryonic lethality, vascular remodeling defects, and enlargement of vascular structures in extraembryonic tissues. We show here that antibodies against the extracellular part of VE-PTP mimic the effects of VE-PTP gene disruption exemplified by vessel enlargement in allantois explants.

VE-PTP maintains the endothelial barrier via plakoglobin and becomes dissociated from VE-cadherin by leukocytes and by VEGF.

We have shown recently that vascular endothelial protein tyrosine phosphatase (VE-PTP), an endothelial-specific membrane protein, associates with vascular endothelial (VE)-cadherin and enhances VE-cadherin function in transfected cells (Nawroth, R., G. Poell, A.

Cell adhesion dynamics at endothelial junctions: VE-cadherin as a major player.

The regulation of endothelial cell contacts is of central importance for the barrier function of the blood vessel wall and for the control of leukocyte extravasation. In addition, the plasticity of endothelial cell contacts is regulated during angiogenesis by growth factors, such as vascular endothelial growth factor and angiopoietin-1. Despite the participation of several adhesion molecules and receptors in the control of endothelial cell contacts, most of the currently known mechanisms involve vascular endothelial cadherin (VE-cadherin), an essential adhesion molecule for the stability of endothelial junctions.

Interaction between SGT1 and cytosolic/nuclear HSC70 chaperones regulates Arabidopsis immune responses.

The conserved eukaryotic protein SGT1 (for Suppressor of G2 allele of skp1) has characteristics of an HSP90 (for heat shock protein 90 kD) cochaperone and in plants regulates hormone responses and Resistance gene-triggered immunity. We affinity-purified SGT1-interacting proteins from Arabidopsis thaliana leaf extracts and identified by mass spectrometry cytosolic heat shock cognate 70 (HSC70) chaperones as the major stable SGT1 interactors. Arabidopsis SGT1a and SGT1b proteins associate with HSC70 in vivo and distribute with HSC70 in the cytosol and nucleus.