| activin A receptor, type IIA | |
| Hgncid: | 173 |
| Symbol: | ACVR2A |
| Altsymbols: | ACVR2 |
| Entrezgene: | 92 |
| Omim: | 102581 |
| Refseq: | NM_001616 |
| Uniprot: | P27037 |
| Chromosome: | 2 |
| Arm: | q |
| Band: | 22.2 |
| Locussupplementarydata: | -23.3 |
| activin A receptor, type IIB | |
| Hgncid: | 174 |
| Symbol: | ACVR2B |
| Entrezgene: | 93 |
| Omim: | 602730 |
| Refseq: | NM_001106 |
| Uniprot: | Q13705 |
| Chromosome: | 3 |
| Arm: | p |
| Band: | 22 |
The activin type 2 receptors belong to a larger TGF-beta receptor family and modulate signals for transforming growth factor beta ligands. These receptors are involved in a host of physiological processes including, growth, cell differentiation, homeostasis, osteogenesis, apoptosis and many other functions. There are two activin type two receptors: ACVR2A and ACVR2B.
Despite the large amount of processes that these ligands regulate, they all operate through essentially the same pathway: A ligand binds to a type 2 receptor, which recruits and trans-phosphorylates a type I receptor. The type I receptor recruits a receptor regulated SMAD (R-SMAD) which it phosphorylates. The RSMAD then translocates to the nucleus where it functions as a transcription factor.
Several ligands that signal through the activin type 2 receptors regulate muscle growth.[1] Myostatin, a TGF-beta superfamily member, is a negative regulator of muscle growth.[1] Myostatin binds to ACVR2B and to a lesser extent ACVR2A. In mice that were ACVR2A −/− (null) mutants there was an increase in all four muscle groups studied (pectoralis, triceps, quadriceps, and gastrocnemious/plantaris muscles).[1] Two of these muscle groups (pectoralis and triceps) were increased in ACVR2B −/− (null) mutants.[1]
Activin plays a significant role in reproduction. ACVR2 receptors are present in the testis during testicular development.[2] ACR2A and ACVR2B was found to be localized primarily in the gonocytes as well as in sertoli cells.[2] These cells are responsive to both autocrine and paracrine activin B signaling, which controls their proliferation.[2] Cells of the epididymis also have ACVR2A receptors present. ACVR2B receptors were found to be localized in the rete testis.[2]
The ACVR2 gene is often found inactivated in prostate cancer and tumors with microsatellite instability.[3]
In a lab, it has been shown that truncated mutations in the ACVR2 gene causes a significant reduction in activin mediated cell signaling. In 58.1% of microsatellite unstable (MSI-H) colorectal cancers the ACVR2A gene has been found mutated. It also plays a role in non-MSI-H colorectal cancers.[4]