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J V Small

Publications and source records attributed to J V Small.

101 records · Page 6Linked to original sources
PubMed1976

Studies on the specificity of smooth-muscle antibodies.

Purified contractile proteins from smooth and striated muscles have been used to test the specificity of human smooth muscle antibodies (SMA) from patients with chronic liver disease (IgG-SMA) and acute hepatitis (IgM-SMA). The reactions, as detected by indirect immunofluorescence, of IgG-SMA with renal vessel walls, renal glomeruli, peritubular fibrils and the luminal part of the tubular cells could be completely abolished by absorption with either smooth muscle or skeletal muscle F-actin, while absorption with myosin and tropomyosin had no effect. The specificity of IgG-SMA for actin was confirmed by their staining of the actin-rich I-bands of skeletal muscle myofibrils and by the blocking of this reaction by pretreatment of myofibrils and isolated smooth muscle cells with smooth muscle myosin subfragment 1 (S-1). IgM-SMA from patients with acute hepatitis-stained renal vessel walls and some sera also stained renal glomeruli. The IgM-SMA titres decreased after absorption both with myosin and F-actin but not with tropomyosin. The reactivity of some IgM-SMA could be blocked by S-1 while others could not. Thus the specificity of IgM-SMA seemed to be variable, and apparently differed from IgG-SMA in some cases.

Absorption↗
PubMedDate not supplied

Complex protein composition of isolated focal adhesions: a two-dimensional gel and database analysis.

Current ideas about the composition of the focal adhesion complexes in cultured cells are based mainly on indirect immunocytochemical data. We here report a two-dimensional (2-D) gel electrophoresis analysis of the focal adhesion associated-structures that remain in the growth substrate after removal of cells by mechanical shearing. Many proteins additional to the known adhesion proteins, and in higher abundance, could be identified. Using selective extraction procedures, employing detergent or gelsolin, these could be classified as either membrane-associated, actin-associated or both. Cross correlation of these polypeptode patterns with a 2-D gel database allowed identification of some proteins, not previously considered as resident of focal adhesions. The data point to a more complex make up of focal adhesions than formerly supposed.

3T3 Cells↗
PubMedDate not supplied

Visualization of actin filaments in keratocyte lamellipodia: negative staining compared with freeze-drying.

Depending on the method of preparation, the actin-rich lamellipodia of motile cells can show very different structural organizations. This situation has been a main contributor to differences in current ideas about the possible mechanisms of cell movement. We have here analyzed the structure of the lamellipodium in whole-mount cytoskeletons using one of the most rapid of crawling cells, the fish keratocyte, employing two procedures considered least damaging to actin filament arrays: freeze-drying and negative staining. At the front of the lamellipodium, where filaments density is the highest, freeze-dried images conveyed the impression of a cross-linked network of very short, interconnected filaments--as previously observed by others--whereas the same regions appeared as a diagonal meshwork of long, more or less straight filaments after negative staining. In general, the linearity of actin filaments was not preserved after freeze-drying, except in situations where the filaments had partially dried down onto the substrate before freezing. In the mid and posterior regions of the lamellipodium the actin filaments appeared to be up to several micrometers long by negative staining, whereas their length was impossible to discern by freeze-drying, owing to filament kinking and aggregation and to the nature of the contrasting procedure, which reveals only the upper layers of filaments. We conclude that while freeze-drying preserves the overall three-dimensional structure of the lamellipodium it also introduces fine-structural distortions in actin that obscure actin filament order. Drying in negative stain appears to stabilise the actin network.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗