Structural maintenance of chromosome 3 (chondroitin sulfate proteoglycan 6, chromosome-associated polypeptide, hCAP, bamacan, basement membrane-associated chondroitin proteoglycan, CSPG6, BAM, BMH, SMC3, SMC3L1)

Function: - role in chromosome cohesion during cell cycle & in DNA repair - component of cohesin complex - interacts with MXI1, MXD3 & MXD4 - interacts with SYCP2 - found in a complex with SMC1A, CDCA5 & RAD21, PDS5A/APRIN & PDS5B/SCC-112 (putative) - forms a heterodimer with SMC1A or SMC1B in cohesin complexes - also found in meiosis-specific cohesin complexes - interacts with NUMA1, & forms a ternary complex with KIF3B & KIFAP3, suggesting a function in tethering the chromosomes to the spindle pole & in chromosome movement - phosphorylated upon DNA damage, probably by ATM or ATR Structure: - the flexible hinge domain, which separates the large intramolecular coiled coil regions, allows the heterotypic interaction with the corresponding domain of SMC1A or SMC1B, forming a V-shaped heterodimer - the two heads of the heterodimer are then connected by different ends of the cleavable RAD21 protein, forming a ring structure (putative) - belongs to the SMC family, SMC3 subfamily Compartment: - nucleus - associates with chromatin - before prophase it is scattered along chromosome arms - during prophase, most of cohesin complexes dissociate from chromatin probably because of phosphorylation by PLK, except at centromeres, where cohesin complexes remain - at anaphase, the RAD21 subunit of the cohesin complex is cleaved, leading to the dissociation of the complex from chromosomes, allowing chromosome separation Pathology: - defects in SMC3 are the cause of Cornelia de Lange syndrome type 3 Note: - originally isolated as a proteoglycan protein (explaining its name); secreted function is uncertain

General

phosphoprotein protein subunit

Properties

SIZE: entity length = 1217 aa MW = 142 kD COMPARTMENT: cell nucleus MOTIF: ATP-binding site NAME: ATP-binding site SITE: 32-39 coiled coil {179-350} coiled coil {393-503} coiled coil {669-916} MOTIF: Ser phosphorylation site {S787} coiled coil {958-989} Ser phosphorylation site {S1013} Ser phosphorylation site {S1065} Ser phosphorylation site {S1067} Ser phosphorylation site {S1074} Ser phosphorylation site {S1083}

Database Correlations

OMIM 606062 UniProt Q9UQE7 PFAM correlations Kegg hsa:9126

References

UniProt :accession Q9UQE7