A 45 amino acid residue domain necessary and sufficient for proteolytic cleavage of the MAP1B polyprotein precursor.
The microtubule-associated proteins 1B and 1A are synthesized as polyprotein precursors which are rapidly cleaved to give rise to heavy and light chains constituting the respective microtubule-associated protein 1B or microtubule-associated protein 1A complex. To identify domains necessary for precursor processing, we expressed microtubule-associated protein 1B deletion mutants in fibroblasts and monitored proteolytic cleavage of the precursor proteins by immunoblot analysis. We found that a novel hydrophilic, proline-rich 45 amino acid domain containing the cleavage site is necessary and sufficient for processing. This domain is conserved in microtubule-associated protein 1A. Additional sequences in the N-terminal half of the heavy chain contribute to the efficiency of cleavage.
Tögel
M
M
Institute of Biochemistry and Molecular Cell Biology, Vienna Biocenter, University of Vienna, Austria.
Eichinger
R
R
Wiche
G
G
Propst
F
F
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D010450:Endopeptidases / Q000378:metabolism; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D008869:Microtubule-Associated Proteins; D011498:Protein Precursors; D011506:Proteins; D011993:Recombinant Fusion Proteins; C085284:microtubule-associated protein 1B; D010450:Endopeptidases