Sorcin (SRI)
The protein contains 198 amino acids for an estimated molecular weight of 21676 Da.
Calcium-binding protein that modulates excitation-contraction coupling in the heart. Contributes to calcium homeostasis in the heart sarcoplasmic reticulum. Modulates the activity of RYR2 calcium channels. (updated: March 4, 2015)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
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Biological Process
Action potential
Calcium ion transport
Cytoplasmic sequestering of transcription factor
Heart development
Intracellular sequestering of iron ion
Muscle organ development
Negative regulation of cardiac muscle contraction
Negative regulation of heart rate
Negative regulation of ryanodine-sensitive calcium-release channel activity
Negative regulation of transcription regulatory region DNA binding
Positive regulation of insulin secretion involved in cellular response to glucose stimulus
Positive regulation of release of sequestered calcium ion into cytosol
Proteolysis
Regulation of calcium ion transport
Regulation of cardiac muscle cell contraction
Regulation of cell communication by electrical coupling
Regulation of cell communication by electrical coupling involved in cardiac conduction
Regulation of heart contraction
Regulation of high voltage-gated calcium channel activity
Regulation of relaxation of muscle
Regulation of release of sequestered calcium ion into cytosol by sarcoplasmic reticulum
Regulation of striated muscle contraction
Signal transduction
Transport
The reference OMIM entry for this protein is 182520
Sorcin; sri
Multidrug-resistance complex, class 4
Mdr complex, class 4
Van der Bliek et al. (1988) showed that the human homolog of the hamster sorcin gene resides on chromosome 7 like the P-glycoprotein-encoding genes (MDR1, 171050; MDR3, 171060). (The sorcin gene was assigned by Southern analysis of DNA from somatic cell hybrids.) Furthermore, gene classes designated 4, 5, and 6 were found to be coamplified with MDR1 and MDR3 in a human ovarian carcinoma cell line, which strongly suggested that the overall structure of the human MDR domain is the same as that in the hamster and mouse in which the domain which is amplified to result in multidrug resistance (MDR) comprises not only genes that encode P-glycoproteins, but also at least 5 unrelated genes, 1 of which encodes the calcium-binding protein sorcin. Sorcin, coded by the class 4 gene, is a small cytosolic protein that is overproduced in many MDR cells. It has a sequence similar to the regulatory light-chain of calpain (114170), including calcium-binding loops of the type found in calmodulin (114180). Van der Bliek et al. (1988) also found that a sorcin-related sequence segregated with human chromosome 4. The total area encompassed by the MDR1, MDR3, and classes 4-6 genes may be as much as 1500 kb. Wang et al. (1995) found that the 22-kD sorcin protein was overexpressed in HOB1/VCR-1.0 cells, a multidrug-resistant human B immunoblastic lymphoma cell line. By PCR with primers based on the sequence of hamster sorcin, the authors recovered a partial human sorcin cDNA. Using the partial cDNA to screen a HOB1/VCR-1.0 library, they isolated cDNAs corresponding to the entire sorcin coding region. The predicted 198-amino acid human protein shares 95% sequence identity with hamster sorcin. Human sorcin contains 4 EF-hand calcium-binding motifs. Purified protein bound calcium in vitro. Southern and Northern blot analysis revealed that the sorcin gene is amplified and overexpressed in HOB1/VCR-1.0 cells. No expression was detected in parental HOB1 cells. Independently, Lee (1996) cloned the human sorcin gene. In both heart and skeletal muscle, the geometry and close spatial relationship between sarcolemmal L-type calcium channels and sarcoplasmic reticulum ryanodine receptors (RyRs, see 180903) is critical in determining the time course of calcium release and excitation-contraction coupling. Meyers et al. (1998) stated that sorcin is 1 of a group of modulators of RyR gating. The authors demonstrated that sorcin also associates with cardiac and skeletal muscle L-type calcium channels specifically within the cytoplasmically oriented C-terminal region of the alpha-1 subunits. See 114204. Meyers et al. (1998) suggested that sorcin is a candidate regulator of interchannel communication during excitation-contraction coupling in heart and skeletal muscle. ... More on the omim web site
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 182520 was added.
Jan. 28, 2016: Protein entry updated
Automatic update: model status changed
Jan. 25, 2016: Protein entry updated
Automatic update: model status changed