Identification and cloning of a novel type I serine/threonine kinase receptor of the TGF-beta/BMP superfamily in rat prostate.

A cDNA clone encoding a new member of the type I serine/threonine kinase receptors of the TGF-beta/BMP superfamily was isolated from a rat prostate cDNA library. The predicted sequence of the encoded protein is 493 amino acids with a molecular weight of 55 kDa. It contains a putative cysteine rich extracellular domain, a transmembrane domain, a conserved type I receptor GS domain and a cytoplasmic serine/threonine kinase domain. The kinase domain shares 80% homology with that of ALK-4 and ALK-5 whose ligands are activin and TGF-beta. Northern blot analysis revealed that this prostate serine/threonine kinase receptor I (PSKR-I) is highly expressed in rat dorsolateral prostate, coagulating gland (anterior prostate), cerebellum and adipose tissue.