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Sequence requirements for precursor cleavage within the constitutive secretory pathway.
T Watanabe1, T Nakagawa, J Ikemizu
1Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
The Journal of Biological Chemistry
|April 25, 1992
Summary
Specific amino acid sequences signal precursor protein cleavage by furin (a Kex2 homolog). This study reveals sequence rules for constitutive precursor cleavage, highlighting the importance of basic residues at specific positions and limitations for hydrophobic residues.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Proteolytic precursor cleavage is essential for protein maturation.
- Furin, a mammalian endoprotease, processes proteins in the constitutive secretory pathway.
- The Arg-X-Lys/Arg-Arg sequence has been identified as a signal for furin-mediated cleavage.
Purpose of the Study:
- To investigate the specific sequence requirements for constitutive precursor cleavage by furin.
- To delineate the rules governing the recognition and cleavage of prorenin by furin.
Main Methods:
- Expression of various prorenin mutants in Chinese hamster ovary (CHO) cells.
- Site-directed mutagenesis to introduce amino acid substitutions around the native Lys-Arg cleavage site.
- Analysis of cleavage patterns of prorenin mutants.
Main Results:
- A basic residue (Lys or Arg) at positions -4 or -6 relative to the cleavage site is necessary, in addition to basic residues at -1 and -2.
- Lysine is preferred over arginine at position -2.
- Arginine is preferred over lysine at position -4.
- Hydrophobic aliphatic amino acids at position 1 are not suitable for cleavage.
Conclusions:
- The study defines precise sequence motifs required for efficient furin-mediated cleavage in the constitutive secretory pathway.
- These findings provide critical insights into the substrate specificity of furin and the regulation of protein processing.