Both type 1 and 2 bone morphogenetic protein receptors have a single transmembrane segment. Additionally, both types have a cysteine-rich extracellular domain and a cytoplasmic serine threonine kinase domain.
The passage describes the shared structural features of both type 1 and type 2 bone morphogenetic protein receptors, including their single transmembrane segment, cysteine-rich extracellular domain, and cytoplasmic serine threonine kinase domain.