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An appropriate response and adaptation to hyperosmolarity, i.e., an external osmolarity that is higher than the physiological range, can be a matter of life or death for all cells. It is especially important for free-living organisms such as the yeast Saccharomyces cerevisiae. When exposed to hyperosmotic stress, the yeast initiates a complex adaptive(More)
DLAR is a receptor-like, transmembrane protein-tyrosine phosphatase in Drosophila that is expressed almost exclusively by developing neurons. Analysis of Dlar loss-of-function mutations shows that DLAR plays a key role during motoneuron growth cone guidance. Segmental nerve b (SNb) motor axons normally exit the common motor pathway, enter the ventral target(More)
An osmosensing mechanism in the budding yeast (Saccharomyces cerevisiae) involves both a two-component signal transducer (Sln1p, Ypd1p and Ssk1p) and a MAP kinase cascade (Ssk2p/Ssk22p, Pbs2p, and Hog1p). The transmembrane protein Sln1p contains an extracellular sensor domain and cytoplasmic histidine kinase and receiver domains, whereas the cytoplasmic(More)
The stress-responsive p38 and JNK MAPK pathways regulate cell cycle and apoptosis. A human MAPKKK, MTK1 (= MEKK4), mediates activation of both p38 and JNK in response to environmental stresses. Using a yeast two-hybrid method, three related proteins, GADD45alpha (= GADD45), GADD45, (= MyD118), and GADD45gamma, were identified that bound to an N-terminal(More)
The neural receptor tyrosine phosphatases DPTP69D, DPTP99A and DLAR are involved in motor axon guidance in the Drosophila embryo. Here we analyze the requirements for these three phosphatases in growth cone guidance decisions along the ISN and SNb motor pathways. Any one of the three suffices for the progression of ISN pioneer growth cones beyond their(More)
Leukocyte antigen-related protein (LAR) is a prototype for a family of transmembrane protein tyrosine phosphatases whose extracellular domain is composed of three Ig and several fibronectin type III (FnIII) domains. Complex alternative splicing of the LAR-FnIII domains 4-8 has been observed. The extracellular matrix laminin-nidogen complex was identified as(More)
A human gene (LAR) that hybridizes to mouse leukocyte common antigen cDNA under relaxed hybridization conditions was isolated. The LAR gene is expressed in a broad range of cells, including T lymphocytes, kidney, and prostate cells. The structure of the protein encoded by the LAR gene was deduced by determining the nucleotide sequences of a 7.7-kb LAR cDNA.(More)
BACKGROUND Regulation of actin structures is instrumental in maintaining proper cytoarchitecture in many tissues. In the follicular epithelium of Drosophila ovaries, a system of actin filaments is coordinated across the basal surface of cells encircling the oocyte. These filaments have been postulated to regulate oocyte elongation; however, the molecular(More)
Very little is known about how cellular osmosensors monitor changes in osmolarity of the environment. Here, we report that in yeast, Sln1 osmosensor histidine kinase monitors changes in turgor pressures. Reductions in turgor caused by either hyperosmotic stress, nystatin, or removal of cell wall activate MAPK Hog1 specifically through the SLN1 branch, but(More)
Cytolytic lymphocytes (CTLs) are characterized by their inclusion of cytoplasmic granules containing effector molecules such as perforin and the serine proteases. Here we describe the cDNA cloning and functional characterization of two related isoforms of a cytolytic granule protein designated TIA-1. Sequence analysis reveals that the 40 kd TIA-1 isoform(More)