A tautomerase-null macrophage migration-inhibitory factor (MIF) gene knock-in mouse model reveals that protein interactions and not enzymatic activity mediate MIF-dependent growth regulation.
Macrophage migration-inhibitory factor (MIF) is an upstream regulator of innate immunity and a potential molecular link between inflammation and cancer. The unusual structural homology between MIF and certain tautomerases, which includes both a conserved substrate-binding pocket and a catalytic N-terminal proline (Pro1), has fueled speculation that an enzymatic reaction underlies MIF's biologic function. To address the functional role of the MIF tautomerase activity in vivo, we created a knock-in mouse in which the endogenous mif gene was replaced by one encoding a tautomerase-null, Pro1-->Gly1 MIF protein (P1G-MIF). While P1G-MIF is completely inactive catalytically, it maintains significant, albeit reduced, binding to its cell surface receptor (CD74) and to the intracellular binding protein JAB1/CSN5. P1G-MIF knock-in mice (mif(P1G/P1G)) and cells derived from these mice show a phenotype in assays of growth control and tumor induction that is intermediate between those of the wild type (mif(+/+)) and complete MIF deficiency (mif(-)(/)(-)). These data provide genetic evidence that MIF's intrinsic tautomerase activity is dispensable for this cytokine's growth-regulatory properties and support a role for the N-terminal region in protein-protein interactions.
Fingerle-Rowson
Günter
G
Clinic I for Internal Medicine, Hematology and Oncology, University Hospital Cologne, Cologne, Germany.
Kaleswarapu
Dayananda Rao
DR
Schlander
Corinna
C
Kabgani
Nazanin
N
Brocks
Tania
T
Reinart
Nina
N
Busch
Raymonde
R
Schütz
Anke
A
Lue
Hongqi
H
Du
Xin
X
Liu
Aihua
A
Xiong
Huabao
H
Chen
Yibang
Y
Nemajerova
Alice
A
Hallek
Michael
M
Bernhagen
Jürgen
J
Leng
Lin
L
Bucala
Richard
R
D000483:Alleles; D019943:Amino Acid Substitution; D000818:Animals; D001564:Benzo(a)pyrene; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology; D047108:Embryonic Development; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology; D055879:Gene Knock-In Techniques; D018390:Gene Targeting; D011905:Genes, ras; D019746:Intramolecular Oxidoreductases / Q000172:deficiency* / Q000378:metabolism*; D008263:Macrophage Migration-Inhibitory Factors / Q000172:deficiency* / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D010641:Phenotype; D011485:Protein Binding; D015398:Signal Transduction; D012878:Skin Neoplasms / Q000139:chemically induced / Q000201:enzymology / Q000473:pathology
D008263:Macrophage Migration-Inhibitory Factors; D001564:Benzo(a)pyrene; D019746:Intramolecular Oxidoreductases; C076231:Mif protein, mouse