Z-discs are organizing centers that establish and maintain myofibril structure and function. Important Z-disc proteins are α-actinin, which cross-links actin thin filaments at the Z-disc and Zasp PDZ domain proteins, which directly interact with α-actinin. Here we investigate the biochemical and genetic nature of this interaction in more detail. Zasp52 is the major Drosophila Zasp PDZ domain pr...

To determine if a living cell is necessary for the incorporation of actin, alpha-actinin, and tropomyosin into the cytoskeleton, we have exposed cell models to fluorescently labeled contractile proteins. In this in vitro system, lissamine rhodamine-labeled actin bound to attachment plaques, ruffles, cleavage furrows and stress fibers, and the binding could not be blocked by prior exposure to un...

Neisseria meningitidis Opc protein is an effective invasin for human endothelial cells. We have investigated novel human endothelial receptors targeted by Opc and observed that Opc-expressing bacteria interacted with a 100 kDa protein in whole-cell lysates of human endothelial and epithelial cells. The identity of the protein was established as alpha-actinin by mass spectrometry. Opc expression...

The E-cadherin/catenin system acts as an invasion suppressor of epithelial malignancies. This invasion suppressive activity seems be mediated not only by the cell adhesive activity of E-cadherin but by other undetermined signaling pathways elicited by beta-catenin. In fact, cancer cells that have infiltrated the stroma reduce the expression of E-cadherin and accumulate beta-catenin. We attempte...

Two species of ~-actinin from rabbit fast skeletal muscles were identified with a monospecific antisera. Designated a-actininlf and c~-actinin~f, their distribution in muscles does not correlate with histochemically defined fast fiber type. Rather, the presence of each correlates with Z-line width and with the expression of different thin filament Ca2+-regulatory complexes, a-Actininlf is expre...

The leukocyte adhesion molecule L-selectin mediates binding to lymph node high endothelial venules (HEV) and contributes to leukocyte rolling on endothelium at sites of inflammation. Previously, it was shown that truncation of the L-selectin cytoplasmic tail by 11 amino acids abolished binding to lymph node HEV and leukocyte rolling in vivo, but the molecular basis for that observation was not ...

Alpha-actinins belong to a family of actin-binding and crosslinking proteins and are expressed in many different cell types. Multiple isoforms of alpha-actinin are found in humans and are encoded by at least four distinct genes. Human skeletal muscle contains two sarcomeric isoforms, alpha-actinin-2 and -3. Previous studies have shown that the alpha-actinins function as anti-parallel homodimers...

The alpha-actinins are an ancient family of actin-binding proteins that play structural and regulatory roles in cytoskeletal organisation and muscle contraction. alpha-actinin-3 is the most-highly specialised of the four mammalian alpha-actinins, with its expression restricted largely to fast glycolytic fibres in skeletal muscle. Intriguingly, a significant proportion ( approximately 18%) of th...

Structural Biology Programme peats, and a calmodulin-like domain at the carboxy ter-It is a dimer composed of D-69012 Heidelberg two 100 kDa monomers that are arranged in an antiparal-Germany lel manner to form a rod-shaped molecule with an actin-binding region at either end (Figure 1C). This arrangement allows ␣-actinin to cross-link actin filaments into Summary tight bundles. Other proteins o...

Within epithelial tissue, cells are held together by specialized lateral junctions. At particular stages of development and in pathological processes such as metastasis, cells break down the intercellular junctions, separate from the epithelial sheet and migrate individually. Despite the importance of these processes, little is understood about the regulatory mechanisms of active cell separatio...