The radial array of cytoplasmic microtubules (MTs) provides routes for intracellular transport and defines spatial organization of cytoplasm through interaction with molecular motors bound to membrane organelles (Kellogg et al., 1994; Hirokawa, 1998). The array is believed to be organized by the centrosome, which is capable of nucleating MTs. Our recent studies of pigment transport (Rodionov an...

Neutrophil extracellular traps (NETs) are chromatin filaments decorated with enzymes from neutrophil cytoplasmic granules. Anti-neutrophil cytoplasmic antibodies (ANCAs) bind to enzymes from neutrophil cytoplasmic granules and are biomarkers for the diagnosis of systemic vasculitides. ANCA diagnostics are based on indirect immunofluorescence (IIF) of ethanol-fixed neutrophils. IIF shows a cytop...

Germ granules are cytoplasmic, non-membranous RNA/protein complexes aggregated in the primordial germ cells of many higher eucaryotes (Eddy, 1975). In the nematode Caenorhabditis elegans, germ granules are called P granules (Strome and Wood, 1982, 1983; Wolf et al., 1983). P granule components are candidate cytoplasmic determinants, specifying germ cell identity in the embryo and gametogenesis ...

The fine structure of the bat thyroid parafollicular cell has been examined at monthly intervals throughout the hibernating period. During November and December parafollicular cells appear either partly or totally degranulated and intact dense secretory granules are relatively sparse. The degranulated cells exhibit an inconspicuous Golgi complex and relatively few lysosome-type bodies. Few degr...

P-selectin is a granule membrane protein of platelets and endothelial cells that is expressed at the plasma membrane after cell activation. To determine which residues in its cytoplasmic tail are important for sorting to storage granules during biosynthesis, we expressed P-selectin mutants in AtT-20, a murine cell line with secretory granules that contain the hormone corticotropin ('ACTH'). Imm...

JGP study shows how synaptotagmins 1 and 7 affect chromaffin cell granule fusion.

The bacterium Ralstonia eutropha forms cytoplasmic granules of polyhydroxybutyrate that are a source of biodegradable thermoplastic. While much is known about the biochemistry of polyhydroxybutyrate production, the cell biology of granule formation and growth remains unclear. Previous studies have suggested that granules form either in the inner membrane, on a central scaffold, or in the cytopl...

The correct mobilization of cytoplasmic granules is essential for the proper functioning of human neutrophils in host defense and inflammation. In this study, we have found that human peripheral blood neutrophils expressed high levels of Rab27a, whereas Rab27b expression was much lower. This indicates that Rab27a is the predominant Rab27 isoform present in human neutrophils. Rab27a was up-regul...

Previous communications from this laboratory delineated the events associated with the in vitro cultivation of unstimulated mouse mononuclear phagocytes (1, 2). These processes included a progressive increase in lysosome-like cytoplasmic granules. In addition, it was shown that two inhibitors of protein synthesis blocked the formation of both granules and hydrolytic enzymes. These data as well ...

Large granular lymphocytes (LGL) are defined as nonadherent mononuclear cells with cytoplasmic azurophilic granules, avid receptors for the Fc portion of IgG, and cytotoxic functions (NK or ADCC activities). In the present study, the granules of LGL isolated from human peripheral blood have been analyzed by enzyme cytochemistry and electron microscopy. It had been found that: (1) in the single ...