| Autor: |
Balyasnikova, I. V., Woodman, Z. L., Albrecht, R. F., II, Natesh, R., Acharya, K. R., Sturrock, E. D., Danilov, S. M. |
| Zdroj: |
Journal of Proteome Research; April 2005, Vol. 4 Issue: 2 p258-267, 10p |
| Abstrakt: |
ACE chimeric proteins and N domain monoclonal antibodies (mAbs) were used to determine the influence of the N domain, and particular regions thereof, on the rate of ACE ectodomain shedding. Somatic ACE (having both N and C domains) was shed at a rate of 20%/24 h. Deletion of the C domain of somatic ACE generated an N domain construct (ACEΔC) which demonstrated the lowest rate of shedding (12%). However, deletion of the N domain of somatic ACE (ACEΔN) dramatically increased shedding (212%). Testicular ACE (tACE) having 36 amino acid residues (heavily O-glycosylated) at the N-terminus of the C domain shows a 4-fold decrease in the rate of shedding (49%) compared to that of ACEΔN. When the N-terminal region of the C domain was replaced with the corresponding homologous 141 amino acids of the N domain (N-delACE) the rate of shedding of the ACEΔN was only slightly decreased (174%), but shedding was still 3.5-fold more efficient than wild-type testicular ACE. Monoclonal antibodies specific for distinct, but overlapping, N-domain epitopes altered the rate of ACE shedding. The mAb 3G8 decreased the rate of shedding by 30%, whereas mAbs 9B9 and 3A5 stimulated ACE shedding 2- to 4-fold. Epitope mapping of these mAbs in conjunction with a homology model of ACE N domain structure, localized a region in the N-domain that may play a role in determining the relatively low rate of shedding of somatic ACE from the cell surface. Keywords: angiotensin I-converting enzyme • monoclonal antibody • shedding • epitope mapping |
| Databáze: |
Supplemental Index |
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