Roles of charged amino acid residues in the cytoplasmic domain of proHB-EGF.
Heparin-binding EGF-like growth factor (HB-EGF) is initially synthesized as a type I transmembrane precursor (proHB-EGF). Proteolytic cleavage of proHB-EGF yields amino- and carboxy-terminal fragments (HB-EGF and HB-EGF-C, respectively). We have previously shown that HB-EGF-C is translocated from the plasma membrane into the nucleus, where it interacts with the transcription repressor, PLZF. Here we characterize the amino acid residues of the cytoplasmic domain of proHB-EGF on cell surface distribution and the interaction of HB-EGF-C with PLZF. The cytoplasmic domain contains three characteristic clusters with charged amino acids. Generation of various mutants of proHB-EGF showed that the arrangement of the charged amino acids in the cytoplasmic domain regulates the distribution of proHB-EGF at the plasma membrane but does not regulate proHB-EGF processing and internalization of HB-EGF-C. Further, the charged amino acids are also required for HB-EGF-C-PLZF interaction. These results indicate that the cytoplasmic domain of proHB-EGF is a multifunctional domain.
Nanba
Daisuke
D
Division of Biochemistry and Molecular Genetics, Department of Molecular and Cellular Biology, Ehime University School of Medicine, Shitsukawa, Shigenobu-cho, Onsen-gun, Ehime 791-0295, Japan.
Toki
Fujio
F
Higashiyama
Shigeki
S
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism*; D004705:Endocytosis; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010957:Plasmids; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism
D000596:Amino Acids; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D004815:Epidermal Growth Factor