Characterization of a cysteine proteinase inhibitor induced during neuronal cell differentiation.
A rat homolog of human cystatin E/M was identified by differential display of transcripts induced during neuronal cell differentiation. A member of the family 2 cystatins, rat cystatin E/M is secreted, glycosylated and developmentally regulated. Rat cystatin E/M is expressed in brain, and is induced during differentiation of a conditionally immortalized E17 rat hippocampal cell line (H19-7) by bFGF or activated Raf via MEK-dependent and -independent signaling pathways. Rat cystatin E/M protein is increased post-transcriptionally in PC12 cells, and the protein is secreted into the medium of primary embryonal hippocampal cultures. Analysis of the K (i) of recombinant His-tagged rat cystatin E/M toward cathepsins B and H revealed that rat cystatin E/M has an inhibitor profile distinct from that of other members of the cystatin family. Motif swapping between rat cystatin E/M and human cystatin C, a well-characterized cystatin, identified some residues that can contribute to the specificity of inhibition. Taken together, these results describe a member of the cystatin family that has a distinct inhibitor profile and may play a role in neuronal development.
Hong
Jia
J
Department of Neurobiology, Pharmacology and Physiology, University of Chicago, Chicago, Illinois 60637, USA.
Yoshida
Keiko
K
Rosner
Marsha Rich
MR
D000818:Animals; D001483:Base Sequence; D002403:Cathepsins / Q000037:antagonists & inhibitors; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D003001:Cloning, Molecular; D055332:Cystatin M; D015891:Cystatins / Q000235:genetics / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000235:genetics* / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D006031:Glycosylation; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009928:Organ Specificity; D016716:PC12 Cells; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
C525104:CST6 protein, human; D055332:Cystatin M; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D011993:Recombinant Fusion Proteins; D020929:Mitogen-Activated Protein Kinase Kinases; D002403:Cathepsins