Molecular cloning and the COOH-terminal processing of gp64, a putative cell-cell adhesion protein of the cellular slime mold Polysphondylium pallidum.
The cellular slime mold Polysphondylium pallidum expresses a cell surface glycoprotein (referred to as gp64), which seems to be implicated in cell-cell adhesion. We identified a near full-length gp64 cDNA (1,104 base) upon screening a P. pallidum lambda gt11 library with a monoclonal antibody. The open reading frame encodes a protein of 320 amino acids with a molecular mass of 32,752 Da; the protein includes hydrophobic segments at both a NH2- and a COOH-terminal ends. By an Edman degradation analysis of S-pyridylethylated gp64 and its COOH-terminal peptide, it was found that the NH2- and COOH-terminal segments are both removed from the precursor protein of gp64. The COOH-terminal segment was isolated from a lysyl endopeptidase digest of gp64 by an affinity method. The COOH-terminal segment was identified at positions 266-279 in the primary sequence deduced from the cDNA sequence. The mature gp64 consisted of 279 amino acid residues and extremely rich in Cys residues (36 Cys/279 amino acids = 12.9%). Although there was already maximal accumulation of gp64 mRNA in vegetative cells, the protein reached a maximal level during aggregation stage, decreased, and then leveled off through the developmental cycle.
Manabe
R
R
Department of Biology, Faculty of Science, Hokkaido University, Sapporo, Japan.
Saito
T
T
Kumazaki
T
T
Sakaitani
T
T
Nakata
N
N
Ochiai
H
H
D000595:Amino Acid Sequence; D001483:Base Sequence; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009235:Myxomycetes / Q000235:genetics* / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins
D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D012331:RNA, Fungal; D014764:Viral Proteins