Stromal Antigen 2 (STAG2)

Stromal cells from blood-forming organs provide the physical support for hematopoietic cell organization. The stroma also produces signals for seeding, renewal, proliferation, and differentiation of stem cells.

STAG2 is expressed as an approximately 140-kD protein that assembles with the cohesin proteins, SMC1 , SMC3 (CSPG6), and SCC1 (RAD21). The cohesin complex also coprecipitates with PDS5, but in a less stable way than the proteins in the cohesin assembly. Immunofluorescence microscopy demonstrated nonnucleolar expression of STAG2 in interphase and early prophase, but expression did not occur again until telophase, with the onset of chromosome decondensation. The expression pattern paralleled those of STAG1, PDS5, and the other cohesin subunits.