Across the plant kingdom, phytochrome (PHY) photoreceptors play an important role during adaptive and developmental responses to light. In , light-activated PHYs accumulate in the nucleus, where they regulate downstream signaling components, such as phytochrome interacting factors (PIFs). PIFs are transcription factors that act as repressors of photomorphogenesis; their inhibition by PHYs leads to substantial changes in gene expression. The nuclear function of PHYs, however, has so far been investigated in only a few non-seed plants. Here, we identified putative target genes of PHY signaling in the moss and found light-regulated genes that are putative orthologs of PIF-controlled genes in Arabidopsis. Phylogenetic analyses revealed that an ancestral PIF-like gene was already present in streptophyte algae, i.e., before the water-to-land transition of plants. The PIF homologs in the genome of resemble Arabidopsis PIFs in their protein domain structure, molecular properties, and physiological effects, albeit with notable differences in the motif-dependent PHY interaction. Our results suggest that PIFs are involved in PHY signaling. The PHY-PIF signaling node that relays light signals to target genes has been largely conserved during land plant evolution, with evidence of lineage-specific diversification.

Cadherin cell-cell adhesion proteins play an important role in modulating the behavior of tumor cells. E-cadherin serves as a suppressor of tumor cell invasion, and when tumor cells turn on the expression of a non-epithelial cadherin, they often express less E-cadherin, enhancing the tumorigenic phenotype of the cells. Here, we show that when A431 cells are forced to express R-cadherin, they dramatically downregulate the expression of endogenous E-and P-cadherin. In addition, we show that this downregulation is owing to increased turnover of the endogenous cadherins via clathrin-dependent endocytosis. p120 ctn binds to the juxtamembrane domain of classical cadherins and has been proposed to regulate cadherin adhesive activity. One way p120 ctn may accomplish this is to serve as a rheostat to regulate the levels of cadherin. Here, we show that the degradation of E-cadherin in response to expression of R-cadherin is owing to competition for p120 ctn .

Desmosomes are prominent cell-cell adhesive junctions found in a variety of epithelial tissues, including the oral epithelium. The transmembrane core of the desmosome is composed of the desmosomal cadherins that interact extracellularly to mediate cell-cell adhesion. The cytoplasmic domain of desmosomal cadherins interact with plaque proteins that in turn interact with the keratin intermediate filament cytoskeleton. Plakophilin 1 is a major desmosomal plaque component that functions to recruit intermediate filaments to sites of cell-cell contact via interactions with desmoplakin. Decreased assembly of desmosomes has been reported in several epithelial cancers. We examined plakophilin-1 expression in an esophageal squamous cell carcinoma tissue microarray and found that plakophilin-1 expression inversely correlates with tumor grade. In addition, we sought to investigate the effect of plakophilin-1 expression on desmosome assembly and cell motility in oral squamous cell carcinoma cell lines. Cell lines expressing altered levels of plakophilin-1 were generated and the ability of these cells to recruit desmoplakin to sites of cell-cell contact was examined. Our results show that decreased expression of plakophilin-1 results in decreased desmosome assembly and increased cell motility and invasion. These data lead us to propose that loss of plakophilin-1 expression during head and neck squamous cell carcinoma (HNSCC) progression may contribute to an invasive phenotype.

The results of this study suggest that the Ober test assesses tightness of structures proximal to the hip joint, such as the gluteus medius and minimus muscles and the hip joint capsule, rather than the ITB.

Cadherins are synthesized with a signal sequence and a proregion that must be removed for optimal adhesive activity. Mutations that prevent processing of cadherins have been implicated in a number of human diseases; thus understanding their processing is critical. In this study, we produced and characterized a number of monoclonal antibodies against the proregion of the desmosomal cadherin, human desmoglein-2, that will facilitate investigations into the processing of this protein. 249