Structural maintenance of chromosomes protein 4 (SMC4)
The protein contains 1288 amino acids for an estimated molecular weight of 147182 Da.
Central component of the condensin complex, a complex required for conversion of interphase chromatin into mitotic-like condense chromosomes. The condensin complex probably introduces positive supercoils into relaxed DNA in the presence of type I topoisomerases and converts nicked DNA into positive knotted forms in the presence of type II topoisomerases. (updated: April 1, 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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| Variant | Description |
|---|---|
| dbSNP:rs35214835 | |
| dbSNP:rs33999879 | |
| dbSNP:rs2164675 |
Biological Process
Cell division
Kinetochore organization
Meiotic chromosome condensation
Meiotic chromosome segregation
Mitotic cell cycle
Mitotic chromosome condensation
Mitotic sister chromatid segregation
The reference OMIM entry for this protein is 605575
Structural maintenance of chromosomes 4; smc4
Chromosome-associated protein c; capc
DESCRIPTION
Members of the structural maintenance of chromosomes, or SMC, family (e.g., SMC1A; 300040) are critical for mitotic chromosome condensation in frogs and for DNA repair in mammals.CLONING
By PCR of human cDNA libraries using degenerate primers based on conserved C-terminal sequences of Xenopus, yeast, and C. elegans SMC proteins, Schmiesing et al. (1998) obtained cDNAs encoding human SMC4 and SMC2 (605576), which they called CAPC and CAPE, respectively. Sequence analysis predicted that the 1,202-amino acid CAPC protein lacks the first 80 residues of the frog sequence but is homologous in the middle coiled-coil region. Northern blot analysis detected a 5.0-kb transcript. Western blot and immunoprecipitation analyses showed that CAPC is expressed as a 165-kD soluble nuclear protein throughout the cell cycle in a variety of cell lines and is associated with CAPE in a heterodimeric complex. Immunofluorescence analysis demonstrated that the proteins are associated with condensed chromosomes in mitotic cells and show dense speckles in interphase nuclei. Microinjection of anti-CAPC or anti-CAPE failed to arrest mitosis in metaphase cells, in contrast to antibody to SMC1A. Nishiwaki et al. (1999) isolated a full-length cDNA encoding CAPC. The 1,288-amino acid CAPC protein shares 77% identity overall with the Xenopus sequence, including preservation of the approximately 200-amino acid N-terminal region containing a nucleotide-binding motif and of the approximately 200-amino acid C-terminal region containing a DA box. Northern blot analysis detected a 4.4-kb transcript in all tissues tested, with most abundant expression in thymus, testis, and colon.GENE FUNCTION
By coimmunoprecipitation and Western blot analysis of HeLa cell nuclear extract, Schmiesing et al. (2000) found that CAPC and CAPE (SMC2) interacted with CNAP1 (NCAPD2; 615638) in a stoichiometric manner. In synchronized HeLa cells, the 3 condensin proteins localized to the cytoplasm during interphase, but a subpopulation of the complex colocalized at specific chromosomal foci. During late G2/early prophase, these foci colocalized with phosphorylated histone H3 (see 602810) and, like phosphorylated histone H3, the condensin foci grew to cover the entire length of chromosomes during mitosis. Following mitosis, the majority of condensin subunits relocalized to the cytoplasm.MAPPING
Using FISH analysis, Nishiwaki et al. (1999) mapped the SMC4 gene to chromosome 3q26.1. ... 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 605575 was added.