TY - JOUR
T1 - Cleavage of precursors by the mitochondrial processing peptidase requires a compatible mature protein or an intermediate octapeptide
AU - Isaya, Grazia
AU - Kalousek, Frantisek
AU - Fenton, Wayne A.
AU - Rosenberg, Leon E.
PY - 1991/4
Y1 - 1991/4
N2 - Many precursors of mitochondrial proteins are processed in two successive steps by independent matrix peptidases (MPP and MIP), whereas others are cleaved in a single step by MPP alone. To explain this dichotomy, we have constructed deletions of all or part of the octapeptide characteristic of a twice cleaved precursor (human ornithine transcarbamylase [pOTC]), have exchanged leader peptide sequences between once-cleaved (human methylmalonyl-CoA mutase [pMUT]; yeast F1ATPase β-subunit [pF1β]) and twicecleaved (pOTC; rat malate dehydrogenase (pMDH); Neurospora ubiquinol-cytochrome c reductase ironsulfur subunit [pFe/S]) precursors, and have incubated these proteins with purified MPP and MIP. When the octapeptide of pOTC was deleted, or when the entire leader peptide of a once-cleaved precursor (pMUT or pF1β) was joined to the mature amino terminus of a twice-cleaved precursor (pOTC or pFe/S), no cleavage was produced by either protease. Cleavage of these constructs by MPP was restored by re-inserting as few as two amino-terminal residues of the octapeptide or of the mature amino terminus of a once-cleaved precursor. We conclude that the mature amino terminus of a twice-cleaved precursor is structurally incompatible with cleavage by MPP; such proteins have evolved octapeptides cleaved by MIP to overcome this incompatibility.
AB - Many precursors of mitochondrial proteins are processed in two successive steps by independent matrix peptidases (MPP and MIP), whereas others are cleaved in a single step by MPP alone. To explain this dichotomy, we have constructed deletions of all or part of the octapeptide characteristic of a twice cleaved precursor (human ornithine transcarbamylase [pOTC]), have exchanged leader peptide sequences between once-cleaved (human methylmalonyl-CoA mutase [pMUT]; yeast F1ATPase β-subunit [pF1β]) and twicecleaved (pOTC; rat malate dehydrogenase (pMDH); Neurospora ubiquinol-cytochrome c reductase ironsulfur subunit [pFe/S]) precursors, and have incubated these proteins with purified MPP and MIP. When the octapeptide of pOTC was deleted, or when the entire leader peptide of a once-cleaved precursor (pMUT or pF1β) was joined to the mature amino terminus of a twice-cleaved precursor (pOTC or pFe/S), no cleavage was produced by either protease. Cleavage of these constructs by MPP was restored by re-inserting as few as two amino-terminal residues of the octapeptide or of the mature amino terminus of a once-cleaved precursor. We conclude that the mature amino terminus of a twice-cleaved precursor is structurally incompatible with cleavage by MPP; such proteins have evolved octapeptides cleaved by MIP to overcome this incompatibility.
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U2 - 10.1083/jcb.113.1.65
DO - 10.1083/jcb.113.1.65
M3 - Article
C2 - 1672532
AN - SCOPUS:0025821619
SN - 0021-9525
VL - 113
SP - 65
EP - 76
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 1
ER -