Secretion impairment of kininogens from the transfected cells

• Published in: Japanese Journal of Pharmacology Vol. 71; no. suppl.1; p. 216
• Main Authors: Hagiwara, Yukari, Hayashi, Izumi, Hoshiko, Shiaeru, Makabe, Osamu, Oh-ishi, Sachiko
• Format: Journal Article
• Language: English; Japanese
• Published: The Japanese Pharmacological Society 1996
• ISSN: 0021-5198
• DOI: 10.1016/S0021-5198(19)37103-3

Severe deficiency of high molecular weight-kininogen (HK) in the plasma of Brown Norway Katholiek (B/N-Ka) strain rat is caused by a secretion defect of the kininogen from its liver, where kininogens are mainly synthesized. We found a point mutation in an amino acid replacement of alanine 163 to threonine in the coding region of HK cDNA of B/N-Ka rat. In T-kininogen (TK) ,the 3rd kininogen in the rat, the alanine residue is conserved at a position 162 and amino acid sequence around the alanine is quite similar to those of HK, but not identical. In this communication, we examined any significance of this amino add of TK for its secretion from cells. TK cDNA was cloned from the liver of B/N-Ka rat. The site-directed mutagenesis for the TK cDNA was designed to delete alanine at a position 162 or to introduce a replacement with threonine, serine, aspartic acid, valine, asparagine or proline. Expression plasmids containing each mutated TK cDNA were constructed for a transient expression in COS-1 cells. Secretion of TK from COS-1 cells into the medium was significantly decreased in cases where the plasmid containing the replacement with Thr or Pro, or containing the deletion, was transfected to the cells. This result coincides well with the previous result in that a secretion of HK from cells was affected by a replacement of Ala at a position 163 to Thr, indicating that the replacement interferes the secretion of not only HK but also TK from the cells. Whether the replacement with Pro or the deletion impedes the secretion of TK by the same mechanism as the replacement with Thr is unclear.