The Shank/ProSAP family of multidomain proteins is known to play an important role in organizing synaptic multiprotein complexes. Here we report a novel interaction between Shank and ␤PIX, a guanine nucleotide exchange factor for the Rac1 and Cdc42 small GTPases. This interaction is mediated by the PDZ domain of Shank and the C-terminal leucine zipper domain and the PDZ domain-binding motif at the extreme C terminus of ␤PIX. Shank colocalizes with ␤PIX at excitatory synaptic sites in cultured neurons. In brain, Shank forms a complex with ␤PIX and ␤PIX-associated signaling molecules including p21-associated kinase (PAK), an effector kinase of Rac1/Cdc42. Importantly, overexpression of Shank in cultured neurons promotes synaptic accumulation of ␤PIX and PAK. Considering the involvement of Rac1 and PAK in spine dynamics, these results suggest that Shank recruits ␤PIX and PAK to spines for the regulation of postsynaptic structure.Dendritic spines are actin-rich morphological specializations in neurons that mediate most excitatory synaptic transmission (1-3). The postsynaptic density (PSD) 1 is a microscopic structure within dendritic spines that is associated with the postsynaptic membrane and contains a variety of scaffolding and signaling proteins (4, 5).The Shank/ProSAP/SSTRIP family of multidomain proteins (Shank1, Shank2, and Shank3) plays important roles in organizing the PSD (6, 7). Shank is a relatively large protein (ϳ200 kDa) and contains various protein interaction domains including, from the N terminus, ankyrin repeats, an SH3 domain, a PDZ domain, a long (Ͼ1000 aa residues) proline-rich region and a SAM domain. The ankyrin repeats interact with ␣-fodrin, an actin-regulating protein, and Sharpin, a protein implicated in Shank multimerization (8, 9). The Shank PDZ domain interacts with the GKAP/SAPAP family of synaptic scaffold proteins and various membrane proteins including the calciumindependent receptor for latrotoxin, somatostatin receptors, and metabotropic glutamate receptors (10 -16). The long proline-rich region of Shank associates with IRSp53 (an insulin receptor tyrosine kinase substrate protein), Homer (an immediate early gene product that binds the group I metabotropic receptors and inositol 1,4,5-trisphosphate receptors), dynamin (a GTPase that regulates endocytosis), and cortactin (a regulator of the cortical actin cytoskeleton) (16 -20). The C-terminal SAM domain mediates multimerization of Shank proteins (10). There are several splice variants of Shank with alternative translational start and stop codons, suggesting that the Shank protein interactions are regulated by alternative splicing (11,12,21,22).Functionally, Shank is involved in the morphogenesis of dendritic spines (3, 23). Overexpression of Shank proteins promotes the maturation of spines in cultured neurons (24). The enhanced spine maturation by Shank requires the interaction of Shank with Homer, a protein that binds to metabotropic glutamate receptors and inositol 1,4,5-trisphosphate receptors (16). In addition, expression of ...

This study showed that tDC therapy in a preclinical model of MI was potentially translatable into an antiremodeling therapy for ischemic tissue repair.

In non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations, acquired resistance to EGFR-tyrosine kinase inhibitors (EGFR-TKI) can occur through a generation of bypass signals such as MET or AXL activation. In this study, we investigated the antitumor activity of NPS-1034, a newly developed drug that targets both MET and AXL, in NSCLC cells with acquired resistance to gefitinib or erlotinib (HCC827/GR and HCC827/ER, respectively). Characterization of H820 cells and evaluation of NPS-1034 efficacy in these cells were also performed. The resistance of HCC827/GR was mediated by MET activation, whereas AXL activation led to resistance in HCC827/ER. The combination of gefitinib or erlotinib with NPS-1034 synergistically inhibited cell proliferation and induced cell death in both resistant cell lines. Accordingly, suppression of Akt was noted only in the presence of treatment with both drugs. NPS-1034 was also effective in xenograft mouse models of HCC827/GR. Although the H820 cell line was reported previously to have T790M and MET amplification, we discovered that AXL was also activated in this cell line. There were no antitumor effects of siRNA or inhibitors specific for EGFR or MET, whereas combined treatment with AXL siRNA or NPS-1034 and EGFR-TKIs controlled H820 cells, suggesting that AXL is the main signal responsible for resistance. In addition, NPS-1034 inhibited cell proliferation as well as ROS1 activity in HCC78 cells with ROS1 rearrangement. Our results establish the efficacy of NPS-1034 in NSCLC cells rendered resistant to EGFR-TKIs because of MET or AXL activation or ROS1 rearrangement. Cancer Res; 74(1); 253-62. Ó2013 AACR.