SR proteins play critical roles in the regulation of pre-mRNA splicing. We show that most human SR protein genes are themselves alternatively spliced, and their alternative splice forms are often targets of a degradation pathway known as nonsense-mediated mRNA decay (NMD). By mining EST databases for sequences corresponding to the 11 human SR protein genes, we have identified premature stop (no...

Pre-mRNA splicing occurs in the spliceosome, which is composed of small ribonucleoprotein particles (snRNPs) and many non-snRNP components. SR proteins, so called because of their C-terminal arginine- and serine-rich domains (RS domains), are essential members of this class. Recruitment of snRNPs to 5' and 3' splice sites is mediated and promoted by SR proteins. SR proteins also bridge splicing...

To decipher the mechanism(s) underlying glucocorticoid action on cardiac contractile function, this study investigated the effects of adrenalectomy and dexamethasone treatment on the contents of sarcoplasmic reticulum (SR) Ca(2+)-cycling proteins, their phosphorylation by endogenous Ca(2+)/calmodulin-dependent protein kinase II (CaM kinase II), and SR Ca(2+) sequestration in the rat myocardium....

In striated muscle, the sarcoplasmic reticulum (SR) Ca2+ release/ryanodine receptor (RyR) channel provides the pathway through which stored Ca2+ is released into the myoplasm during excitation-contraction coupling. Various luminal Ca2+-binding proteins are responsible for maintaining the free [Ca2+] at 10(-3)-10(-4) M in the SR lumen; in skeletal-muscle SR, it is mainly calsequestrin. Here we s...

Western General Hospital generates different forms of the mRNA and functionally Crewe Road different proteins. This is accomplished by modulation Edinburgh EH4 2XU of the basic splicing mechanism, frequently involving changes in the relative activities of antagonistic factors. Key players are the SR protein family. These consist of Introduction one or two RNA-recognition motifs (RRMs) plus a C-...

For those of us used to hearing with our ears, it is difficult to imagine how the fish or amphibian perceives its environment on the basis of information from the lateral line sensory system. The lateral line system detects vibrations in the water, a process that has been termed ‘svenning’ — after Sven Dijkgraaf (1908–1995), a founder figure in lateral line research — and is neatly summarised i...

Although members of the serine (S)- and arginine (R)-rich splicing factor family (SR proteins) were initially purified on the basis of their splicing activity in the nucleus, there is recent documentation that they exhibit carbohydrate-binding activity at the cell surface. In contrast, galectins were isolated on the basis of their saccharide-binding activity and cell surface localization. Surpr...

HPV-16 (human papillomavirus type 16) is a small dsDNA (double-stranded DNA) virus which infects mucosal epithelial tissue of the cervix. Epithelial tissue is composed of a basal layer of cells, capable of division, and a number of suprabasal layers, wherein the cells become more differentiated the closer to the surface of the epithelium they become. Expression of viral proteins is dependent up...

The U1 small nuclear ribonucleoprotein particle (U1 snRNP) 70K protein (U1-70K), one of the three U1 snRNP-specific proteins, is implicated in basic and alternative splicing of nuclear pre-mRNAs. We have used the Arabidopsis U1-70K in the yeast two-hybrid system to isolate cDNAs encoding proteins that interact with it. This screening has resulted in the isolation of two novel plant serine/argin...

Calumenin is a multiple EF-hand Ca2+-binding protein located in the endo/sarcoplasmic reticulum of mammalian hearts. Calumenin belongs to the CREC family of Ca2+-binding proteins having multiple EF-hands. Ca2+ homeostasis in the sarcoplasmic reticulum (SR) of mammalian hearts is maintained by RyR2, SERCA2 and other associated SR resident proteins. Evidence suggests that calumenin interacts with...