Disease relevance of Sri

• Cells infected with MVA/Sor MVA/S-HA synthesized a 200-kDa protein, which was recognized by antibody raised against a synthetic peptide of SARS-CoV S or the epitope tag in Western blot analyses [1].
• In vivo adenoviral transfer of sorcin reverses cardiac contractile abnormalities of diabetic cardiomyopathy [2].

High impact information on Sri

• The contribution of sorcin to multidrug resistance, if any, remains to be tested [3].
• We show here that one of these genes (class 4) codes for a small phosphorylated, cytosolic protein, sorcin/V19, known to be overproduced by many MDR cell lines [3].
• These may account for the known phosphorylation of sorcin [3].
• The identity of this protein with sorcin was established by comparison with the amino acid sequence of two peptides from mouse sorcin [3].
• Immunocytochemical staining shows that sorcin localizes to the dyadic space of ventricular cardiac myocytes [4].

Biological context of Sri

• A search for annexin A7 binding partners with advanced biochemical methods confirmed sorcin as the major binding protein [5].
• Together with previous work, these observations suggest the following gene order: Cen-Sor/Pgy-1-rl-T31H-En-2-other loci [6].
• The mapped region is located on mouse chromosome 5 and includes the three mdr genes, the gene for the calcium-binding sorcin protein, and a gene with unknown function designated class 5 [7].
• Because sorcin decreased the amplitude of the [Ca2+]i transient without affecting the amplitude or kinetics of ICa, the overall effect of sorcin was to reduce the "gain" of excitation-contraction coupling [4].
• In turn, the lack of complex formation between the sorcin Ca(2+) binding domain (33-198) and synexin maps the annexin binding site to the N-terminal region of the sorcin polypeptide chain [8].

Anatomical context of Sri

• However, in vivo GFP-tagged annexin A7 and sorcin appeared to redistribute mainly independently from each other in wild type and in mutant astrocytes [5].
• Sorcin levels are higher in Pgp+ CD4 cells than in Pgp- CD4 cells of young mice and increase with age in CD4 cells, consistent with the hypothesis that sorcin interferes with calcium signals in the age-sensitive Pgp+ T cell subset [9].

Associations of Sri with chemical compounds

• Chemosensitisation by verapamil and cyclosporin A in mouse tumour cells expressing different levels of P-glycoprotein and CP22 (sorcin) [10].
• Sorcin is an EF-hand protein that confers the property of caffeine-activated intracellular Ca(2+) release in nonmuscle cells by interacting with RyR2 [2].

Other interactions of Sri

• In addition, the gene for the calcium-binding protein, sorcin, was coamplified in eight of the nine MDR sublines [11].
• The interaction may involve similar structural motifs in the two proteins, namely GGYY and GYGG in sorcin and GYPP in synexin [8].
• The proteins galectin-1, sorcin, and vimentin were found to be induced 9-, 9-, and 25-fold, respectively, in the PKD proteome relative to the wild type [12].

Analytical, diagnostic and therapeutic context of Sri

• Surface plasmon resonance experiments show that at neutral pH the stability of the complex between sorcin and annexin VII (synexin) increases dramatically between 3 and 6 microM calcium; at the latter cation concentration the K(D) value is 0.63 microM [8].

References