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A Point Mutation in the Juxtamembrane Stalk of Human Angiotensin I-converting Enzyme Invokes the Action of a Distinct Secretase.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

  • Marwan Alfalah
  • Edward T. Parkin
  • Ralf Jacob
  • Edward D. Sturrock
  • Reinhard Mentele
  • Anthony J. Turner
  • Nigel M. Hooper
  • Hassan Y. Naim
<mark>Journal publication date</mark>15/06/2001
<mark>Journal</mark>Journal of Biological Chemistry
Issue number24
Number of pages5
Pages (from-to)21105-21109
Publication StatusPublished
<mark>Original language</mark>English


Angiotensin I-converting enzyme (ACE) is one of a number of integral membrane proteins that is proteolytically shed from the cell surface by a zinc metallosecretase. Mutagenesis of Asn631 to Gln in the juxtamembrane stalk region of ACE resulted in more efficient secretion of the mutant protein (ACENQ) as determined by pulse-chase analysis. In contrast to the wild-type ACE, the cleavage of ACENQ was not blocked by the metallosecretase inhibitor batimastat but by the serine protease inhibitor, 1,3-dichloroisocoumarin. Incubation of the cells at 15 °C revealed that ACENQ was cleaved in the endoplasmic reticulum, and mass spectrometric analysis of the secreted form of the protein indicated that it had been cleaved at the Asn635-Ser636 bond, three residues N-terminal to the normal secretase cleavage site at Arg638-Ser639. These data clearly show that a point mutation in the juxtamembrane region of an integral membrane protein can invoke the action of a mechanistically and spatially distinct secretase. In light of this observation, previous data on the effect of mutations in the juxtamembrane stalk of shed proteins being accommodated by a single secretase having a relaxed specificity need to be re-evaluated.