TY - JOUR
T1 - Fly versus man
T2 - Evolutionary impairment of nucleolar targeting affects the degradome of Drosophila's Taspase1
AU - Wünsch, Désirée
AU - Hahlbrock, Angelina
AU - Heiselmayer, Christina
AU - Bäcker, Sandra
AU - Heun, Patrick
AU - Goesswein, Dorothee
AU - Stöcker, Walter
AU - Schirmeister, Tanja
AU - Schneider, Günter
AU - Krämer, Oliver H.
AU - Knauer, Shirley K.
AU - Stauber, Roland H.
PY - 2015/5/1
Y1 - 2015/5/1
N2 - Human Taspase1 is essential for development and cancer by processing critical regulators, such as the mixed-lineage leukemia protein. Likewise, its ortholog, trithorax, is cleaved by Drosophila Taspase1 (dTaspase1), implementing a functional coevolution. To uncover novel mechanism regulating protease function, we performed a functional analysis of dTaspase1 and its comparisontothe human ortholog.dTaspase1contains an essential nucleophile threonine195, catalyzing cis cleavage into its a- and b-subunits. A cell-based assay combined with alanine scanning mutagenesis demonstrated that the target cleavage motif for dTaspase1 (Q3[F/I/L/M]2D1 G1'X2X3'v) differs significantly from the human ortholog (Q3[F,I,L,V]2D1G1'X2'X3'vD4'), predicting an enlarged degradome containing 70 substrates for Drosophila. In contrast to human Taspase1, dTaspase1 shows no discrete localization to the nucleus/nucleolus due to the lack of the importin-a/nucleophosmin1 interaction domain (NoLS) conserved in all vertebrates. Consequently, dTaspase1 interacts with neither the Drosophila nucleoplasmin-like protein nor human nucleophosmin1. The impact of localization on the protease's degradome was confirmed by demonstrating that dTaspase1 did not efficiently process nuclear substrates, such as upstream stimulatoryfactor2.However,geneticintroductionofthe NoLS into dTaspase1 restored its nucleolar localization, nucleophosmin1 interaction, and efficient cleavage of nuclearsubstrates.Wereportthatevolutionaryfunctional divergence separating vertebrates from invertebratescan be achieved for proteases by a transport/localizationregulated mechanism.
AB - Human Taspase1 is essential for development and cancer by processing critical regulators, such as the mixed-lineage leukemia protein. Likewise, its ortholog, trithorax, is cleaved by Drosophila Taspase1 (dTaspase1), implementing a functional coevolution. To uncover novel mechanism regulating protease function, we performed a functional analysis of dTaspase1 and its comparisontothe human ortholog.dTaspase1contains an essential nucleophile threonine195, catalyzing cis cleavage into its a- and b-subunits. A cell-based assay combined with alanine scanning mutagenesis demonstrated that the target cleavage motif for dTaspase1 (Q3[F/I/L/M]2D1 G1'X2X3'v) differs significantly from the human ortholog (Q3[F,I,L,V]2D1G1'X2'X3'vD4'), predicting an enlarged degradome containing 70 substrates for Drosophila. In contrast to human Taspase1, dTaspase1 shows no discrete localization to the nucleus/nucleolus due to the lack of the importin-a/nucleophosmin1 interaction domain (NoLS) conserved in all vertebrates. Consequently, dTaspase1 interacts with neither the Drosophila nucleoplasmin-like protein nor human nucleophosmin1. The impact of localization on the protease's degradome was confirmed by demonstrating that dTaspase1 did not efficiently process nuclear substrates, such as upstream stimulatoryfactor2.However,geneticintroductionofthe NoLS into dTaspase1 restored its nucleolar localization, nucleophosmin1 interaction, and efficient cleavage of nuclearsubstrates.Wereportthatevolutionaryfunctional divergence separating vertebrates from invertebratescan be achieved for proteases by a transport/localizationregulated mechanism.
KW - Cancer
KW - Development
KW - Leukemia
KW - Protease
KW - Threonine aspartase
U2 - 10.1096/fj.14-262451
DO - 10.1096/fj.14-262451
M3 - Article
C2 - 25634959
AN - SCOPUS:84932599372
SN - 0892-6638
VL - 29
SP - 1973
EP - 1985
JO - The FASEB Journal
JF - The FASEB Journal
IS - 5
ER -