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PubMed2003

The different effects of endocrine-disrupting chemicals on estrogen receptor-mediated transcription through interaction with coactivator TRAP220 in uterine tissue.

An endocrine-disrupting chemical (EDC) can alter endocrine functions through a variety of mechanisms, including nuclear receptor-mediated changes in protein synthesis, interference with membrane receptor binding, steroidogenesis or synthesis of other hormones. Although major chemicals have been shown to disrupt estrogenic actions mainly through their binding to estrogen receptor (ER) or androgen receptor, it is not clear how EDCs affect endocrine functions in vivo. We present evidence that the EDCs bisphenol A and phthalate activate ER-mediated transcription through interaction with TRAP220. Moreover, bisphenol A had positive effects on the interaction between ER-beta and TRAP220 and on the expression of ER-beta and TRAP220 compared with phthalate and estradiol in uterine tIssue. These data suggested that some EDCs might alter endocrine function through the change of the receptor and coactivator levels in uterine tIssue and through the different effect on the interaction between ERs and coactivator TRAP220.

Animals↗
PubMed1999

Interferon regulatory factor 1 mediates the interferon-gamma induction of the human immunoproteasome subunit multicatalytic endopeptidase complex-like 1.

Proteasomes generate antigenic peptides from intracellular proteins for presentation to the immune system by the major histocompatibility complex class I molecules. The antiviral cytokine IFN-gamma alters the catalytic specificity of proteasomes by inducing the synthesis of an alternative set of three proteolytically active proteasome subunits. We have analyzed the mechanism of IFN-gamma induction for the IFN-gamma-induced subunit multicatalytic endopeptidase complex-like 1 (MECL1). The human MECL1 promoter contains two interferon-stimulated response elements (ISREs), generally known to bind members of the interferon regulatory factor (IRF) family. The importance of these elements for IFN-gamma induction of MECL1 was addressed by transfecting an endothelial cell line with MECL1 promoter constructs. By deletions and mutations of the ISRE sequences, we demonstrated that both ISREs were needed for full IFN-gamma induction of the reporter gene. The second (downstream) ISRE was essential for both IFN-gamma-induced and basal transcriptional activity of the promoter. In electrophoretic mobility shift assays, anti-IRF-1 antibodies supershifted an IFN-gamma-induced protein binding specifically to both ISRE sequences, whereas IRF-2 bound the second ISRE before induction. Co-transfection of IRF-1 resulted in induced MECL1 promoter activity in the absence of IFN-gamma. These data indicate that the IFN-gamma induction of human MECL1 is mediated by IFN-gamma-induced IRF-1.

B-Lymphocytes↗
PubMed1996

The herpes simplex virus type 1 transactivator ICPO mediates aberrant intracellular localization of the viral helicase/primase complex subunits.

The infected cell polypeptide 0 (ICP0) protein of herpes simplex virus type 1 (HSV-1) is a promiscuous transactivator. When expressed by transfection, ICP0 forms spherical structures in the nucleus. Using a double-label immunofluorescence assay, we have found that the HSV-1 helicase/primase complex subunits accumulate within ICP0 structures in cotransfected cells. This phenomenon was also observed in cells coexpressing ICP0 and UL6, a protein thought to be involved in the cleavage and/or packaging of viral genomes. ICP0 structures were found to be proteinaceous by immunoelectron microscopy. These results suggest that ICP0 may interact nonspecifically with a variety of viral proteins.

Animals↗
PubMed2005

E1A-CR3 interaction-dependent and -independent functions of mSur2 in viral replication of early region 1A mutants of mouse adenovirus type 1.

mSur2, a subunit of the Mediator complex, is required for efficient mouse adenovirus type 1 (MAV-1) replication (L. Fang, J. L. Stevens, A. J. Berk, and K. R. Spindler, J. Virol. 78:12888-12900, 2004). We examined the contributions of early-region 1A (E1A) to mSur2 function in MAV-1 replication with E1A mutant viruses. At a multiplicity of infection (MOI) of 1, viruses containing CR3 replicated better in Sur2+/+ mouse embryonic fibroblasts (MEFs) than in Sur2-/- MEFs. In contrast, viruses lacking CR3 replicated no better in Sur2+/+ than in Sur2-/- MEFs. This result supports the hypothesis that the E1A CR3-mSur2 interaction is important for MAV-1 replication. However, at an MOI of 0.05, viruses lacking CR3 showed replication defects in Sur2-/- MEFs compared to Sur2+/+ MEFs, suggesting an E1A CR3 interaction-independent function of mSur2 in MAV-1 replication in cell culture. Paradoxically, CR1Delta, CR2Delta, and CR3Delta mutant viruses replicated slightly more efficiently than wild-type (wt) MAV-1 and E1A null mutant viruses in Sur2-/- MEFs at an MOI of 0.05. Coinfection of Sur2-/- MEFs with wt MAV-1 and CR1Delta, CR2Delta, or CR3Delta mutant viruses rescued the defects of wt MAV-1 replication. This result suggests that an inhibiting effect on wt E1A protein expression and/or E1A function might account for the severe viral replication defect of MAV-1 in Sur2-/- MEFs at an MOI of 0.05. Moreover, titrations of virus yields from infected brains of inbred strains of mice showed that E1A null and CR3Delta mutant viruses had a significant defect in virus replication compared to wt MAV-1. This result supports the hypothesis that the MAV-1 E1A-mSur2 interaction is important in MAV-1 replication in mice.

ATP-Binding Cassette Transporters↗
PubMed2001

Characterization of mediator complexes from HeLa cell nuclear extract.

A number of mammalian multiprotein complexes containing homologs of Saccharomyces cerevisiae Mediator subunits have been described recently. High-molecular-mass complexes (1 to 2 MDa) sharing several subunits but apparently differing in others include the TRAP/SMCC, NAT, DRIP, ARC, and human Mediator complexes. Smaller multiprotein complexes (approximately 500 to 700 kDa), including the murine Mediator, CRSP, and PC2, have also been described that contain subsets of subunits of the larger complexes. To evaluate whether these different multiprotein complexes exist in vivo in a single form or in multiple different forms, HeLa cell nuclear extract was directly resolved over a Superose 6 gel filtration column. Immunoblotting of column fractions using antisera specific for several Mediator subunits revealed one major size class of high-molecular-mass (approximately 2-MDa) complexes containing multiple mammalian Mediator subunits. No peak was apparent at approximately 500 to 700 kDa, indicating that either the smaller complexes reported are much less abundant than the higher-molecular-mass complexes or they are subcomplexes generated by dissociation of larger complexes during purification. Quantitative immunoblotting indicated that there are about 3 x 10(5) to 6 x 10(5) molecules of hSur2 Mediator subunit per HeLa cell, i.e., the same order of magnitude as RNA polymerase II and general transcription factors. Immunoprecipitation of the approximately 2-MDa fraction with anti-Cdk8 antibody indicated that at least two classes of Mediator complexes occur, one containing CDK8 and cyclin C and one lacking this CDK-cyclin pair. The approximately 2-MDa complexes stimulated activated transcription in vitro, whereas a 150-kDa fraction containing a subset of Mediator subunits inhibited activated transcription.

Cell Extracts↗
PubMed2003

Investigations of intermediates appearing in the reassociation of the light-harvesting 1 complex of Rhodospirillum rubrum.

We investigated the temperature-mediated reassociation of the B820 subunit of Rs. rubrum to form a light-harvesting 1 complex (LH 1). By combining several spectroscopic techniques with global spectral data analysis fitting, we present evidence for the occurence of two spectral intermediates that appear during the reassociation process. At high temperatures, halfway the reassociation reaction, a prominent intermediate appears that has an absorption maximum around 850 nm, a fluorescence maximum around 860-867 nm, a high anisotropy (0.3 to 0.4) and a circular dichroism spectrum with three or four bands with alternating signs. At lower temperatures, more towards the end of the reassociation process, a second intermediate tends to appear that has an absorption maximum around 860 nm, a fluorescence maximum around 885 nm, a medium to high anisotropy (0.1 to 0.3) and a circular dichroism spectrum with two bands with alternating signs. The latter circular dichroism spectrum has a blueshifted zero-crossing compared to the spectrum of the LH 1 complex. Both intermediates have the spectroscopic features of a small oligomer. In the Q(y) region, the fluorescence anisotropy of both intermediates slightly increases at longer excitation wavelengths, indicative for energy transfer among the pigments within the intermediate oligomers.

Journal Article↗
PubMed2001

Laminin synthesis and the adhesion characteristics of immortalized human corneal epithelial cells to laminin isoforms.

We have studied the synthesis of laminins (Ln) and determined the specific integrins mediating the adhesion of immortalized human corneal epithelial cells to mouse Ln-1, and human Lns-5 and -10. Immunofluorescence microscopy of the cells demonstrated integrin alpha(2), alpha(3), alpha(6), beta(1)and beta(4)subunits, integrins alpha(6)and beta(4)being found in a typical 'leopard-skin' like manner. Immunoprecipitation studies showed that the cells produced alpha 3, beta 3 and gamma 2 chains of Ln-5, but not Lns-1 or -10. In culture Ln-5 was found as small plaques beneath the adhering cells within 1 hr, while in 4 hr widely spread Ln-5 plaques were observed in colocalization with beta(4)integrin subunit. By using a quantitative cell adhesion assay and function-blocking monoclonal antibodies we showed that integrin beta(1)subunit plays a role in mediating corneal epithelial cell adhesion to mouse Ln-1. However, none of the available function-blocking antibodies to integrin alpha-subunits inhibited the adhesion. Integrin alpha(3)beta(1)complex mediated the adhesion of corneal epithelial cells to human Lns-5 and -10. Integrin complex alpha(3)beta(1), as well as laminin alpha(3)chain, was also shown to mediate cell adhesion to newly produced endogenous Ln-5. The present results show that integrin alpha(3)beta(1)complex mediates the adhesion of corneal epithelial cells to Lns-5 and -10, while a yet unknown integrin alpha subunit appears to play a role in the adhesion to Ln-1. The results also show that among corneal basement membrane laminins, Ln-5 is synthetized by epithelial cells while Ln-10 may be a product of keratocytes.

Animals↗
PubMed2005

Induction of the RelB NF-kappaB subunit by the cytomegalovirus IE1 protein is mediated via Jun kinase and c-Jun/Fra-2 AP-1 complexes.

We recently demonstrated that the cytomegalovirus (CMV) immediate-early 1 (IE1) protein induces transcription of the gene encoding the RelB NF-kappaB subunit. The mechanism of this activation has been explored here. We report that the induction of the relB promoter by IE1 protein is mediated via activation of JNK and AP-1. The region controlling relB promoter induction was mapped to the upstream approximately 600-bp region between -1694 and -1096 bp. IE1 stimulated AP-1 activity in NIH 3T3 cells. Competition electrophoretic mobility shift assay (EMSA) confirmed the presence of one bona fide AP-1 element centered at -1503 bp. Introduction of a G-to-C mutation in the AP-1 binding site within the distal region of the relB promoter eliminated its activation by IE1 in both NIH 3T3 fibroblasts and vascular smooth muscle cells (SMCs). Supershift EMSA identified c-Jun, Fra-2, and c-Fos in AP-1 binding complexes in IE1 transfected NIH 3T3 cells. IE1 induced c-Jun phosphorylation, and treatment with SP600125, a selective JNK inhibitor, as well as overexpression of JNK-binding domain of JIP1, blocked IE1-mediated induction of AP-1 and relB promoter activity in NIH 3T3 cells and SMCs. Ectopic expression of c-Jun plus Fra-2, but not c-Fos, induced relB promoter activity. The relB promoter has two proximal NF-kappaB elements, and c-Jun/Fra-2 worked in synergy with p50/p65 NF-kappaB complexes. Overall, these findings demonstrate for the first time the role of AP-1 in transcriptional regulation of a gene encoding an NF-kappaB subunit, and its involvement in induction of RelB activity by the CMV IE1 protein.

Animals↗
PubMed2002

In vivo association of adenovirus large E1A protein with the human mediator complex in adenovirus-infected and -transformed cells.

The adenovirus large E1A protein activates transcription from early viral promoters by a mechanism that requires a forty amino acid zinc finger activation domain in E1A conserved region 3 (CR3). Recent results indicate that activation by a Gal4 DNA-binding domain-E1A-CR3 fusion requires an interaction between the E1A-CR3 zinc finger and the Sur2 subunit of the mammalian Mediator (of transcription) complex. Although several host proteins have been shown to bind stably to E1A proteins in adenovirus-infected and -transformed cells, an in vivo interaction with Mediator complex subunits has not been described previously. Using immunoprecipitation and gel filtration analyses of nuclear extracts prepared from HeLa cells infected with adenovirus 5 or mutants that express either large or small E1A specifically and from adenovirus 5-transformed cells, we report here that large E1A, but not small E1A, binds to Mediator complex in vivo. Only approximately 1 to 10% of large E1A is bound to Mediator complex at 18 h postinfection and in transformed cells, probably explaining why Mediator complex subunits were not identified among cellular E1A-binding proteins described earlier. Surprisingly, even though extracted Mediator can quantitatively bind to an E1A-CR3 affinity column, only on the order of 1% of cellular Mediator complex is bound by E1A in vivo. Much of the large E1A bound to Mediator in 293 cells is in a stable complex that includes RNA polymerase II, leading us to suggest that the interaction of E1A-CR3 with Mediator stabilizes the interaction of Mediator with the polymerase. This stabilization of the interaction between Mediator and RNA polymerase II may contribute to the mechanism of activation by E1A-CR3.

Adenovirus E1A Proteins↗
PubMed2005

Structural basis of chaperone-subunit complex recognition by the type 1 pilus assembly platform FimD.

Adhesive type 1 pili from uropathogenic Escherichia coli are filamentous protein complexes that are attached to the assembly platform FimD in the outer membrane. During pilus assembly, FimD binds complexes between the chaperone FimC and type 1 pilus subunits in the periplasm and mediates subunit translocation to the cell surface. Here we report nuclear magnetic resonance and X-ray protein structures of the N-terminal substrate recognition domain of FimD (FimD(N)) before and after binding of a chaperone-subunit complex. FimD(N) consists of a flexible N-terminal segment of 24 residues, a structured core with a novel fold, and a C-terminal hinge segment. In the ternary complex, residues 1-24 of FimD(N) specifically interact with both FimC and the subunit, acting as a sensor for loaded FimC molecules. Together with in vivo complementation studies, we show how this mechanism enables recognition and discrimination of different chaperone-subunit complexes by bacterial pilus assembly platforms.

Adhesins, Escherichia coli↗
PubMed1993

Human neuronal voltage-dependent calcium channels: studies on subunit structure and role in channel assembly.

Voltage-dependent calcium (Ca2+) channels, expressed in the CNS, appear to be multimeric complexes comprised of at least alpha 1, alpha 2 and beta subunits. Previously, we cloned and expressed human neuronal alpha 1, alpha 2 and beta subunits to study recombinant channel complexes that display properties of those expressed in vivo. The alpha 1B-mediated channel subtype binds omega-conotoxin (CgTx) GVIA with high affinity and exhibits properties of N-type voltage-dependent Ca2+ channels. Here we describe several alpha 2 and beta splice variants and report results on the expression of omega-CgTx GVIA binding sites, assembly of the subunit complex and biophysical function of alpha 1B-mediated channel complexes containing some of these splice variants. We optimized recombinant expression in human embryonic kidney (HEK) 293 cells of alpha 1B alpha 2b beta 1 subunit complexes by controlling the expression levels of subunit mRNAs and monitored cell surface expression by binding of omega-CgTx GVIA to the alpha 1B subunit. Co-expression of either alpha 2b or beta 1 subunits with an alpha 1B subunit increased expression of binding sites while the most efficient expression was achieved when both alpha 2b and beta 1 subunits were co-expressed with an alpha 1B subunit. The presence of alpha 2b affects the affinity of omega-CgTx GVIA binding and barium (Ba2+) current magnitudes, although it does not appear to alter kinetic properties of the Ba2+ current. This is the first evidence of an alpha 2 subunit modulating the binding affinity of a cell-surface Ca2+ channel ligand. Our results demonstrate that alpha 1, alpha 2 and beta subunits together contribute to the efficient assembly and functional expression of voltage-dependent Ca2+ channel complexes.

Amino Acid Sequence↗
PubMed2002

Mutational analyses of the photosynthetic reaction center-bound triheme cytochrome subunit and cytochrome c2 in the purple bacterium Rhodovulum sulfidophilum.

The purple photosynthetic bacterium Rhodovulum sulfidophilum has an unusual reaction center- (RC-) bound cytochrome subunit with only three hemes, although the subunits of other purple bacteria have four hemes. To understand the electron-transfer pathway through this subunit, three mutants of R. sulfidophilum were constructed and characterized: one lacking the RC-bound cytochrome subunit, another one lacking cytochrome c(2), and another one lacking both of these. The mutant lacking the RC-bound cytochrome subunit was grown photosynthetically with about half the growth rate of the wild type, indicating that the presence of the cytochrome subunit, while not indispensable, is still advantageous for the photosynthetic electron transfer to support its growth. The mutant lacking both the cytochrome subunit and cytochrome c(2) showed a slower rate of growth by photosynthesis (about a fourth of that of the wild type), indicating that cytochrome c(2) is the dominant electron donor to the RC mutationally devoid of the cytochrome subunit. On the other hand, the mutant lacking only the cytochrome c(2) gene grew photosynthetically as fast as the wild type, indicating that cytochrome c(2) is not the predominant donor to the RC-bound triheme cytochrome subunit. We further show that newly isolated soluble cytochrome c-549 with a redox midpoint potential of +238 mV reduced the photooxidized cytochrome subunit in vitro, suggesting that c-549 mediates the cytochrome c(2)-independent electron transfer from the bc(1) complex to the RC-bound cytochrome subunit. These results indicate that the soluble components donating electrons to the RC-bound triheme cytochrome subunit are somewhat different from those of other purple bacteria.

Alphaproteobacteria↗
PubMed1997

The extracellular domain of the sodium pump beta isoforms determines complex stability with alpha 1.

Both subunits of the Na,K-ATPase are encoded by several genes giving rise to at least six isozymes. To examine whether beta isoforms assemble with alpha 1 in a selective manner, we have overexpressed wild-type and chimeric beta subunits in L929 cells and examined assembly as a function of resistance towards detergent-mediated dissociation. In the presence of digitonin all beta chimeras coimmunoprecipitate the endogenous alpha 1 subunit. Only beta proteins with the ectodomain of beta 1 coimmunoprecipitate alpha 1 in the presence of Triton X-100. All beta chimeras stimulate Na,K-ATPase activity in L929 cells. These data indicate that the beta subunit ectodomains mediate interactions with alpha 1 and influence the stability of this complex.

Animals↗
PubMed1988

Identification of a neuronal laminin receptor: an Mr 200K/120K integrin heterodimer that binds laminin in a divalent cation-dependent manner.

Neuronal interactions with extracellular matrix (ECM) components are crucial for axon growth and guidance during development and nerve regeneration. Laminin (LN), a prominent ECM glycoprotein, promotes neuronal survival and axon growth. To identify neuronal receptors for LN, we looked for cell surface proteins on the neuronal cell line B50 that bind LN. An integrin alpha/beta 1 dimeric receptor was identified and purified using lectin and LN affinity chromatography. The purified integrin contains two subunits with Mrs of 200 K and 120 K that bind LN specifically in the presence, but not the absence, of divalent cations (Ca2+/Mg2+ or Ca2+/Mn2+). The Mr 120 K protein was identified as the rat integrin beta 1 subunit using two beta 1 subunit-specific antibodies, and was shown to form a noncovalent complex with the Mr 200K putative alpha subunit. Since neurons and neuronal cell lines express similar integrin beta 1-class heterodimers that mediate attachment and process outgrowth on LN, the Mr 200K/120K complex identified here is likely to be an important laminin receptor used by neurons. This integrin may also mediate binding to LN by many nonneuronal cell types.

Animals↗
PubMed1993

Oocyte maturation in starfish is mediated by the beta gamma-subunit complex of a G-protein.

The stimulation of meiotic maturation of starfish oocytes by the hormone 1-methyladenine is mimicked by injection of beta gamma subunits of G-proteins from either retina or brain. Conversely, the hormone response is inhibited by injection of the GDP-bound forms of alpha i1 or alpha t subunits, or by injection of phosducin; all of these proteins should bind free beta gamma. alpha-subunit forms with reduced affinity for beta gamma (alpha i1 or alpha t bound to hydrolysis-resistant GTP analogs, or alpha i1-GMPPCP treated with trypsin to remove the amino terminus of the protein) are less effective inhibitors of 1-methyladenine action. These results indicate that the beta gamma subunit of a G-protein mediates 1-methyladenine stimulation of oocyte maturation.

Adenine↗
PubMed2001

Modulation of cytoplasmic dynein ATPase activity by the accessory subunits.

The microtubule-based motor molecule cytoplasmic dynein has been proposed to be regulated by a variety of mechanisms, including phosphorylation and specific interaction with the organelle-associated complex, dynactin. In this study, we examined whether the intermediate chain subunits of cytoplasmic dynein are involved in modulation of ATP hydrolysis, and thereby affect motility. Treatment of testis cytoplasmic dynein under hypertonic salt conditions resulted in separation of the intermediate chains from the remainder of the dynein molecule, and led to a 4-fold enhancement of ATP hydrolysis. This result suggests that the accessory subunits act as negative regulators of dynein heavy chain activity. Comparison of ATPase activities of dyneins with differing intermediate chain isoforms showed significant differences in basal ATP hydrolysis rates, with testis dynein 7-fold more active than dynein from brain. Removal of the intermediate chain subunits led to an equalization of ATPase activity between brain and testis dyneins, suggesting that the accessory subunits are responsible for the observed differences in tissue activity. Finally, our preparative procedures have allowed for the identification and purification of a 1:1 complex of dynein with dynactin. As this interaction is presumed to be mediated by the dynein intermediate chain subunits, we now have defined experimental conditions for further exploration of dynein enzymatic and motility regulation.

Adenosine Triphosphate↗
PubMed2004

Integration of the NfkappaB p65 subunit into the vitamin D receptor transcriptional complex: identification of p65 domains that inhibit 1,25-dihydroxyvitamin D3-stimulated transcription.

Resistance to the action of vitamin D (D) occurs in response to tumor necrosis factor-alpha (TNF-alpha), an effect mediated by nuclear factor kappa B (NfkappaB). To determine the mechanism of NfkappaB inhibition of D-stimulated transcription, chromatin immunoprecipitation assays (CHIP) were done in osteoblastic ROS 17/2.8 cells that had been treated with TNF-alpha or transfected with the p65 subunit of NfkappaB. These treatments caused stable incorporation of p65 into the transcription complex bound to the vitamin D response element (VDRE) of the osteocalcin promoter. Deletion analysis of p65 functional domains revealed that the p65 N-terminus and a midmolecular region were both required for the inhibitory action of p65. Pull-down assays were done using an immobilized glutathione S-transferase (GST)-VDR fusion protein to study the effect of p65 on VDR binding to steroid coactivator-1 (SRC-1), a major D-dependent coactivator. p65 inhibited VDR-SRC-1 binding in a dose-dependent manner. Mutations of p65 that abrogated the inhibitory effect on D-stimulated transcription also failed to inhibit VDR-SRC-1 binding. The inhibitory effect of p65 on VDR transactivation was not due to recruitment of a histone deacetylase (HDAC), since inhibition was not relieved by the HDAC inhibitors sodium butyrate or trichostatin A. Overexpression of SRC-1 or the general coactivators, Creb binding protein or SRC-3, also failed to relieve p65 inhibition of transcription. In addition, Chip assays revealed that TNF-alpha treatment prevented D recruitment of SRC-1 to the transcription complex. These results show that TNF-alpha inhibition of vitamin D-action includes stable integration of p65 in the VDR transcription complex. Once anchored to proteins within the complex, p65 disrupts VDR binding to SRC-1, thus decreasing the efficiency of D-stimulated gene transcription.

Calcitriol↗
PubMed2002

C. elegans PAT-4/ILK functions as an adaptor protein within integrin adhesion complexes.

BACKGROUND: Mammalian integrin-linked kinase (ILK) was identified in a yeast two-hybrid screen for proteins binding the integrin beta(1) subunit cytoplasmic domain. ILK has been implicated in integrin-mediated signaling and is also an adaptor within integrin-associated cytoskeletal complexes. RESULTS: We identified the C. elegans pat-4 gene in previous genetic screens for mutants unable to assemble integrin-mediated muscle cell attachments. Here, we report that pat-4 encodes the sole C. elegans homolog of ILK. In pat-4 null mutants, embryonic muscle cells form integrin foci, but the subsequent recruitment of vinculin and UNC-89 as well as actin and myosin filaments to these in vivo focal adhesion analogs is blocked. Conversely, PAT-4/ILK requires the ECM component UNC-52/perlecan, the transmembrane protein integrin, and the novel cytoplasmic attachment protein UNC-112 to be properly recruited to nascent attachments. Transgenically expressed "kinase-dead" ILK fully rescues pat-4 loss-of-function mutants. We also identify UNC-112 as a new binding partner for ILK. CONCLUSIONS: Our data strengthens the emerging view that ILK functions primarily as an adaptor protein within integrin adhesion complexes and identifies UNC-112 as a new ILK binding partner.

Animals↗