ACVR2A (activing A type 2 receptor) is a transmembrane receptor that binds activin and acts as a growth and differentiation factor during development. ACVR2A also drives oligodendrocyte differentiation and myelination, and the ACVR2A/ACVR2B signaling pathway functions to regulate myelin repair after brain injury in infants. Dysregulation of ACVR2A expression is relevant to neurological disorders such as cerebral palsy and multiple sclerosis. ACVR2A is associated with susceptibility to preeclampsia and also with addiction; it is upregulated during withdrawal from and after re-exposure to some addictive drug stimulants. In immunohistochemistry, ACVR2A has cytoplasmic and membranous positivity in all tissues. References: Science Signaling. 2015. 8(386), ec196, DOI: 10.1126/scisignal.aad0323; Front Neurosci. 2018; 12: 697, PMID: 30356877; Acta Neuropathol. 2018; 135(6): 887–906, PMID: 29397421; Proc. Natl. Acad. Sci. U.S.A. 102 (50): 18117–22, PMID: 16330774;