The polyglutamine-binding protein 1 (PQBP1) has been linked to several X-linked intellectual disability disorders and progressive neurodegenerative diseases. While it is currently known that PQBP1 localizes in nuclear speckles and is engaged in transcription and splicing, we have now identified a cytoplasmic pool of PQBP1. Analysis of PQBP1 complexes revealed six novel interacting proteins, nam...

This study on human neutrophils was conducted to measure the kinetics of degranulation of the different cytoplasmic granules into phagocytic vacuoles, and to relate the timing of these events to the burst of respiration that accompanies phagocytosis by these cells. Purified neutrophils were incubated with latex particles opsonized with human immunoglobulin (Ig)G, and phagocytosis was stopped at...

The effect of differentiation induction by a tumor-promoting phorbol diester, 12-O-tetradecanoylphorbol-13-acetate (TPA) on a clonal human megakaryoblastic cell line, MEG-O1s, was investigated, and a prominent response was demonstrated. The cells became weakly adherent, developed conspicuous cytoplasmic blebs, and displayed mature megakaryocytic characteristics by light microscopy such as the d...

A fraction isolated from the anterior pituitary glands of rats castrate for 8 weeks contained essentially a single cytoplasmic constituent with which the major portion of the gonadotropic hormone activity was associated. The glands were homogenized in an 0.25 M sucrose + 7.3 per cent polyvinylpyrrolidone (PVP) solution and fractionated by differential centrifugation to give a heterogeneous smal...

The present investigation is concerned with the use of the post-formalin ammoniacal silver reaction to detect the arginine-rich cationic proteins in human polymorphonuclear leukocytes at the ultrastructural level. These proteins appear to function as neutral proteases in antibacterial action and as mediators of inflammation. Originally, the ammoniacal silver reaction relied upon primary fixatio...

Injections of hemoglobin were given to rats in order to produce hemosiderosis, and selected hemosiderin granules in sectioned cells of proximal convoluted tubules were studied by means of electron microscopy. When examined at high resolution, many of the dense particles that were present in hemosiderin granules proved to have the structure that characterizes the iron hydroxide micelles of molec...

Computer-aided three-dimensional reconstruction of serial ultrathin sections revealed that freshly prepared monocytes from human blood contained endogenous peroxidase (PO) not only in cytoplasmic granules, but also in long contorted tubules and in complex elements, which consisted of both tubular and granular components. The various PO-positive elements formed an intricate system, which was sep...

The composition and pH of atrial-specific granules of rat heart were determined by electron probe x-ray microanalysis and fluorescence microscopy, respectively. The high (75 mmol/kg of dry weight) calcium content and higher than cytoplasmic concentration of chloride in atrial-specific granules were visualized in high-resolution x-ray maps. The Cl- content of granules and cytoplasm decreased and...

In this study, melanophore cytodifferentiation in the fins of xanthic goldfish that had been exposed to osmotic stress for 18 days was investigated. It was found that multi-vesicular bodies (MVB) are not the only type of premelanosome. Granules having a homogeneous matrix also function as premelanosomes. The presence of acid phosphatase reaction product inside the melanin granules indicated tha...

Capacitance measurements were applied to mouse pancreatic beta-cells to elucidate the cellular mechanisms underlying biphasic insulin secretion. We report here that only <50 of the beta-cell's >10,000 granules are immediately available for release. The releasable granules tightly associate with the voltage-gated alpha(1C) Ca(2+) channels, and it is proposed that the release of these granules ac...