du ce ▁their ▁signals ▁through ▁the ▁formation ▁of ▁heter omer ic ▁complex es ▁of ▁ 2 ▁different ▁types ▁of ▁ser ine ▁( th re on ine ) ▁kin ase ▁re cept ors : ▁type ▁I ▁re cept ors ▁of ▁about ▁ 5 0 - 5 5 ▁k D ▁and ▁type ▁II ▁re cept ors ▁of ▁about ▁ 7 0 - 8 0 ▁k D . ▁Type ▁II ▁re cept ors ▁bind ▁lig ands ▁in ▁the ▁absence ▁of ▁type ▁I ▁re cept ors , ▁but ▁they ▁require ▁their ▁respective ▁type ▁I ▁re cept ors ▁for ▁signal ing , ▁whereas ▁type ▁I ▁re cept ors ▁require ▁their ▁respective ▁type ▁II ▁re cept ors ▁for ▁lig and ▁binding . ▁ ▁The ▁B MP R 1 B ▁re ceptor ▁plays ▁a ▁role ▁in ▁the ▁formation ▁of ▁middle ▁and ▁proxim al ▁ph al anges . ▁ ▁C lin ical ▁significance ▁▁ ▁Mut ations ▁in ▁this ▁gene ▁have ▁been ▁associated ▁with ▁primary ▁pul mon ary ▁hy pert ension . ▁ ▁In ▁the ▁ch ick ▁emb ry o , ▁it ▁has ▁been ▁shown ▁that ▁B MP R 1 B ▁is ▁found ▁in ▁prec art il agin ous ▁cond ens ations . ▁B MP R 1 B ▁is ▁the ▁major ▁trans du cer ▁of ▁signals ▁in ▁these ▁cond ens ations ▁as ▁demonstrated ▁in ▁experiments ▁using ▁const itut ively ▁active ▁B MP R 1 B ▁re cept ors . ▁B MP R 1 B ▁is ▁a ▁more ▁effective ▁trans du cer ▁of ▁G DF 5 ▁than ▁B MP R 1 A .