For ultrastructural localization of acid mucosubstances in rabbit granulocytes, bone marrow and buffy coat specimens were fixed with formalin, glutaraldehyde, or osmium tetroxide, sectioned at 40 micro, and stained with the Rinehart and Abul-Haj solution of dialyzed iron (DI). Heterophils revealed DI staining on the outer surface of the plasma membrane, in the Golgi complex involved in primary ...

Poly(A)-binding protein 1 (PABP1) has a fundamental role in the regulation of mRNA translation and stability, both of which are crucial for a wide variety of cellular processes. Although generally a diffuse cytoplasmic protein, it can be found in discrete foci such as stress and neuronal granules. Mammals encode several additional cytoplasmic PABPs that remain poorly characterised, and with the...

Mutations in the gene encoding Fused in Sarcoma (FUS) cause amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. FUS is a predominantly nuclear DNA- and RNA-binding protein that is involved in RNA processing. Large FUS-immunoreactive inclusions fill the perikaryon of surviving motor neurons of ALS patients carrying mutations at post-mortem. This sequestration of FUS is predi...

Fused in sarcoma/translocated in liposarcoma (FUS/TLS) is one of causative genes for familial amyotrophic lateral sclerosis (ALS). In order to identify binding partners for FUS/TLS, we performed a yeast two-hybrid screening and found that protein arginine methyltransferase 1 (PRMT1) is one of binding partners primarily in the nucleus. In vitro and in vivo methylation assays showed that FUS/TLS ...

Differentiation and maturation of myeloid cells is characterized by the sequential acquisition of two distinct cytoplasmic granule subsets, azurophil granules and specific granules. We recently showed the existence of a third granule subset, gelatinase granules. To investigate whether appearance of gelatinase granules marks a further step in maturation of myeloid cells beyond the appearance of ...

Trans-activating response region (TAR) DNA-binding protein of 43 kDa (TDP-43) is an RNA-binding protein that is mutated in familial amyotrophic lateral sclerosis (ALS). Disease-linked mutations in TDP-43 increase the tendency of TDP-43 to aggregate, leading to a corresponding increase in formation of stress granules, cytoplasmic protein/RNA complexes that form in response to stress. Although th...

We analyzed transmission electron micrographs of human lung mast cells by digitized planimetry and point counting to determine the cross-sectional areas of two distinct cytoplasmic organelles: specific granules and lipid bodies. Specific granules have a limiting membrane and often contain one or more cylindrical scroll-like inclusions. By contrast, lipid bodies are on average much larger than g...

Cells have developed different mechanisms to respond to stress, including the formation of cytoplasmic foci known as stress granules (SGs). SGs are dynamic and formed as a result of stress-induced inhibition of translation. Despite enormous interest in SGs due to their contribution to the pathogenesis of several human diseases, many aspects of SG formation are poorly understood. SGs induced by ...

Tap/NXF1, the founding member of the evolutionarily conserved NXF (Nuclear RNA export Factor) family of proteins, is required for the nuclear export of bulk poly(A)+ RNAs. In mice, three additional NXF family genes (NXF2, NXF3, NXF7) have been identified and characterized to date. Cumulative data suggest that NXF family members play roles, not only in nuclear mRNA export, but also in various as...

Polarized radial arrays of cytoplasmic microtubules (MTs) with minus ends clustered at the cell center define the organization of the cytoplasm through interaction with microtubule motors bound to membrane organelles or chromosomes. It is generally assumed that the radial organization results from nucleation of MTs at the centrosome. However, radial MT array can also be attained through self-or...