A heparin binding protein whose expression increases during differentiation of embryonal carcinoma cells to parietal endoderm cells: cDNA cloning and sequence analysis.
A cDNA clone isolated from a lambda gt11 expression library of teratocarcinoma OTT6050 specifies for a glycoprotein with a molecular weight of about 44,000. The new glycoprotein was termed heparin binding protein-44 (HBP-44), since it was absorbed to a heparin-agarose column and was eluted from it by a buffer containing 1.5 M NaCl. HBP-44 mRNA was intensely expressed in PYS-2 parietal endoderm cells and in the kidney, and the RNA level increased about 10-fold during differentiation of F9 embryonal carcinoma cells to parietal endoderm cells. From the cDNA sequence, HBP-44 was concluded to be rich in charged amino acids, and large segments of the protein appeared to form alpha-helixes. The protein was considered to be anchored to the membrane by a cluster of hydrophobic amino acids present in the N-terminal region. Indeed, the N-terminal sequence of HBP-44 was homologous to asialoglycoprotein receptor, which is anchored to the membrane by the N-terminal region. Furthermore, a portion of the N-terminal region of HBP-44 was homologous to the leucine zipper domain. Except for the N-terminal region, HBP-44 had over-all homology with structural proteins such as myosin heavy chain. We propose that HBP-44 is extruded from plasma membranes and interacts with heparin and related molecules and that it is involved in the interactions of plasma membranes with basement membranes.
Furukawa
T
T
Department of Biochemistry, Faculty of Medicine, Kagoshima University.
Ozawa
M
M
Huang
R P
RP
Muramatsu
T
T
D000595:Amino Acid Sequence; D001212:Asialoglycoproteins / Q000032:analysis; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000737:chemistry; D002454:Cell Differentiation; D003001:Cloning, Molecular; D054278:Embryonal Carcinoma Stem Cells; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D007120:Immunochemistry; D026563:LDL-Receptor Related Protein-Associated Protein; D037102:Lectins / Q000494:pharmacology; D008969:Molecular Sequence Data; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D037121:Plant Lectins; D010980:Platelet Membrane Glycoproteins / Q000096:biosynthesis* / Q000737:chemistry; D012334:RNA, Neoplasm / Q000032:analysis; D015183:Restriction Mapping; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
D001212:Asialoglycoproteins; D002352:Carrier Proteins; D006023:Glycoproteins; D026563:LDL-Receptor Related Protein-Associated Protein; D037102:Lectins; D037121:Plant Lectins; D010980:Platelet Membrane Glycoproteins; D012334:RNA, Neoplasm; C036554:dolichos biflorus agglutinin