Functional complexes between YAP2 and ZO-2 are PDZ domain-dependent, and regulate YAP2 nuclear localization and signalling

he Hippo pathway regulates the size of organs by controlling two opposing processes: proliferation and apoptosis. YAP2 (Yes kinase-associated protein 2), one of the three isoforms of YAP, is a WW domain-containing transcriptional co-activator that acts as the effector of the Hippo pathway in mammalian cells. In addition to WW domains, YAP2 has a PDZ-binding motif at its C-terminus. We reported previously that this motif was necessary for YAP2 localization in the nucleus and for promoting cell detachment and apoptosis. In the present study, we show that the tight junction protein ZO (zonula occludens)-2 uses its first PDZ domain to form a complex with YAP2. The endogenous ZO-2 and YAP2 proteins co-localize in the nucleus. We also found that ZO-2 facilitates the nuclear localization and pro-apoptotic function of YAP2, and that this activity of ZO-2 is PDZ-domain-dependent. The present paper is the first report on a PDZ-based nuclear translocation mechanism. Moreover, since the Hippo pathway acts as a tumour suppressor pathway, the YAP2-ZO-2 complex could represent a target for cancer therapy

The Tandem PDZ Protein Syntenin Interacts with the Aminoacyl tRNA Synthetase Complex in a Lysyl-tRNA Synthetase-Dependent Manner

Syntenin-1 is a tandem PDZ protein that binds a diverse array of signaling molecules that are often associated with cell adhesion and intracellular trafficking. With the use of a MS-based functional proteornics approach, we identified several members of the aminoacyl-tRNA synthetase macromolecular (ARS) complex in a syntenin-1 pull down assay. Interaction of these proteins with syntenin-1 was confirmed by co-immunoprecipitation from cultured cells. We demonstrate a direct interaction of syntenin-1 with lysyl-tRNA synthetase (KRS), which contains a PDZ binding motif at its C-terminus. This motif is important for the interaction of the entire complex with syntenin-1. A point mutation in the PDZ2 domain of syntenin-1 abrogates interaction with KRS. As a result, other components of the ARS complex no longer co-immunoprecipitate with syntenin-1. We further show that syntenin-1 regulates KRS activity. These findings suggest that syntenin-1 is an adaptor modulating the activity of KRS

TAZ interacts with zonula occludens-1 and-2 proteins in a PDZ-1 dependent manner

AbstractThe transcriptional coactivator TAZ recognizes L/PPxY motifs in transcription factors like Runx1/2 through its WW domain. We show that the first PDZ domain of zona occludens-1 (ZO-1) and 2 (ZO-2) interacts with the carboxy-terminal PDZ binding motif of TAZ. Deletion of this motif abrogates binding. ZO-2 colocalizes with TAZ in the nucleus of MDCK cells and ZO-2 expression alters TAZ localization in human embryonic kidney cells. Luciferase assays demonstrate ZO-2 inhibition of TAZ-mediated transactivation. We propose that zonula occludens is a negative regulator of TAZ and suggest that selected tight junction proteins control nuclear translocation and activity of TAZ.Structured summaryMINT-7994937: ZO-2 (uniprotkb:Q95168) binds (MI:0407) to TAZ (uniprotkb:Q9EPK5) by pull down (MI:0096) MINT-7994900, MINT-7994835, MINT-7994885: ZO-1 (uniprotkb:Q07157) physically interacts (MI:0915) with TAZ (uniprotkb:Q9EPK5) by pull down (MI:0096) MINT-7995020: ZO-2 (uniprotkb:Q9UDY2) and TAZ (uniprotkb:Q9GZV5) colocalize (MI:0403) by fluorescence microscopy (MI:0416)MINT-7994953: ZO-1 (uniprotkb:Q07157) binds (MI:0407) to TAZ (uniprotkb:Q9EPK5) by pull down (MI:0096) MINT-7994970: TAZ (uniprotkb:73990382) and ZO-2 (uniprotkb:Q95168) colocalize (MI:0403) by fluorescence microscopy (MI:0416) MINT-7994867: TAZ (uniprotkb:Q9EPK5) physically interacts (MI:0915) with ZO-2 (uniprotkb:Q9UDY2) by pull down (MI:0096) MINT-7994988: TAZ (uniprotkb:Q9GZV5) and ZO-1 (uniprotkb:Q07157) colocalize (MI:0403) by fluorescence microscopy (MI:0416) MINT-7994999: TAZ (uniprotkb:Q9EPK5) and ZO-2 (uniprotkb:Q95168) colocalize (MI:0403) by fluorescence microscopy (MI:0416) MINT-7994922, MINT-7994853: ZO-2 (uniprotkb:Q95168) physically interacts (MI:0915) with TAZ (uniprotkb:Q9EPK5) by pull down (MI:0096

Fragmin60 encodes an actin-binding protein with a C2 domain and controls actin Thr-203 phosphorylation in Physarum plasmodia and sclerotia.

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The PDZ2 domain of zonula occludens-1 and-2 is a phosphoinositide binding domain

Zonula occludens proteins (ZO) are postsynaptic density protein-95 discs large-zonula occludens (PDZ) domain-containing proteins that play a fundamental role in the assembly of tight junctions and establishment of cell polarity. Here, we show that the second PDZ domain of ZO-1 and ZO-2 binds phosphoinositides (PtdInsP) and we identified critical residues involved in the interaction. Furthermore, peptide and PtdInsP binding of ZO PDZ2 domains are mutually exclusive. Although lipid binding does not seem to be required for plasma membrane localisation of ZO-1, phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P (2)) binding to the PDZ2 domain of ZO-2 regulates ZO-2 recruitment to nuclear speckles. Knockdown of ZO-2 expression disrupts speckle morphology, indicating that ZO-2 might play an active role in formation and stabilisation of these subnuclear structures. This study shows for the first time that ZO isoforms bind PtdInsPs and offers an alternative regulatory mechanism for the formation and stabilisation of protein complexes in the nucleus