ACTR1B (beta-centractin) is an actin-related protein that functions as a stoichiometric minor subunit of the cytosolic 20S dynactin complex PMID:7696711. It partitions predominantly to the cytosolic fraction with no detectable free pool, residing within dynactin at a fixed ratio of approximately 1:15 relative to alpha-centractin, which establishes its identity as a constitutive structural component of this complex rather than an independently acting protein PMID:7696711. Beyond its membership in dynactin, ACTR1B abundance is modulated in a cell-type-specific manner: it is differentially altered in human platelets upon glycoprotein VI activation PMID:20107233 and down-regulated in dendritic cells pulsed with high-metastatic-potential hepatocellular carcinoma lysates, where its reduction tracks with diminished CD86 expression and impaired allostimulatory capacity [PMID:17619203, PMID:17925177]. No direct functional dissection of ACTR1B's role within dynactin or in these cellular contexts has been characterized in the available corpus.
| Year | Confidence | Finding | PMIDs | Journal |
|---|---|---|---|---|
| 1994 | High | Beta-centractin (ACTR1B) is an actin-related protein that localizes predominantly to the cytosolic fraction as a component of the 20S dynactin complex, with no evidence for a free pool; it exists in a constant ratio of approximately 1:15 (beta:alpha) relative to alpha-centractin within the dynactin complex. | PMID:7696711 | Molecular biology of the cell |
| 2010 | Low | Beta-centractin (ACTR1B) protein abundance is differentially altered in human platelets upon specific activation of glycoprotein VI (GPVI), indicating that GPVI signaling modulates beta-centractin levels and cytoskeletal organization in platelets. | PMID:20107233 | Blood |
| 2007 | Low | Down-regulation of beta-centractin in dendritic cells pulsed with high-metastatic-potential HCC cell lysates is associated with reduced CD86 expression and impaired allostimulatory capacity (mixed lymphocyte reaction), suggesting beta-centractin supports normal DC function. | PMID:17619203, PMID:17925177 | Journal of cancer research and clinical oncology |