The signal recognition particle (SRP)-mediated translocation of proteins across the RER is a GTP dependent process. Analysis of the primary amino acid sequence of one protein subunit of SRP (SRP54), as well as the alpha subunit of the SRP receptor (SR alpha), has indicated that these proteins contain predicted GTP binding sites. Several point mutations confined to the GTP binding consensus elem...

Complementary DNA representing the genomic M RNA segment of the Prospect Hill (PH) Hantavirus was cloned and its nucleotide sequence determined. The PH virus M RNA segment is 3707 nucleotides in length and has a long open reading frame in the viral complementary-sense RNA with a coding capacity of 1142 amino acids. The predicted gene product of the PH virus M segment was compared with the corre...

A lipophilic anion, tetraphenylboron (TPB-)-induced Ca2+ release from fragmented sarcoplasmic reticulum (SR) of frog skeletal muscle was monitored by chlortetracycline fluorescence. TPB- caused change in surface charge of the membrane and in the protein conformation with a time course similar to that of the Ca2+ release. Tetraphenylarsonium (TPA+) inhibited these effects of TPB-. Change in surf...

BACKGROUND Heart failure is a complex syndrome characterized by cardiac contractile impairment with high mortality. Defective intracellular Ca2+ homeostasis is the central cause under this scenario and tightly links to ultrastructural rearrangements of sarcolemmal transverse tubules and the sarcoplasmic reticulum (SR); however, the modulators of the SR architecture remain unknown. The SR has be...

decreased cardiomyocyte SR-mitochondrial contact length by 30% and reduced the content of SR-associated proteins in mitochondria-associated membranes. This was associated with decreased mitochondrial Ca uptake (despite unchanged mitochondrial membrane potential) but increased steady-state and caffeine-induced SR Ca release. Accordingly, Ca -induced stimulation of Krebs cycle dehydrogenases duri...

The scavenger receptors (SRs) comprise structurally and functionally divergent groups of cell surface and secreted proteins that play an important role in innate immune defenses. Searching translated chicken genomic databases revealed many proteins homologous to mammalian SRs. SR mediated immune functions (oxidative burst, degranulation, phagocytosis, nitric oxide (NO) production, and cytokine ...

In Arabidopsis, pre-mRNAs of serine/arginine-rich (SR) proteins undergo extensive alternative splicing (AS). However, little is known about the cis-elements and trans-acting proteins involved in regulating AS. Using a splicing reporter (GFP-intron-GFP), consisting of the GFP coding sequence interrupted by an alternatively spliced intron of SCL33, we investigated whether cis-elements within this...

SR proteins are essential pre-mRNA splicing factors that act at the earliest stages of splice-site recognition and spliceosome assembly, as well as later in the splicing pathway. SR proteins consist of one or two RNA-recognition motifs and a characteristic arginine/serine-rich C-terminal RS domain. The RS domain, which is extensively phosphorylated, mediates the subcellular localization of indi...

The universally conserved signal recognition particle (SRP) and SRP receptor (SR) mediate the cotranslational targeting of proteins to cellular membranes. In contrast, a unique chloroplast SRP in green plants is primarily dedicated to the post-translational targeting of light harvesting chlorophyll a/b binding (LHC) proteins. In both pathways, dimerization and activation between the SRP and SR ...

Eukaryotic cells have to prevent the export of unspliced pre-mRNAs until intron removal is completed to avoid the expression of aberrant and potentially harmful proteins. Only mature mRNAs associate with the export receptor Mex67/TAP and enter the cytoplasm. Here we show that the two shuttling serine/arginine (SR)-proteins Gbp2 and Hrb1 are key surveillance factors for the selective export of s...