title: Glycoprotein gp130 of dictyostelium discoideum influences macropinocytosis and adhesion.
abstract: Glycoprotein gp130, found on the plasma membrane of Dictyostelium discoideum amoebae, was postulated previously to play a role in phagocytosis. The gene for gp130 was cloned and when translated, yielded a 768 amino acid preproprotein of 85.3 kDa. It had nearly 40% similarity to the 138 kDa family of glycoproteins implicated in sexual cell fusion during macrocyst formation in D. discoideum. The difference between the calculated size and observed M(r) of 130 kDa on protein gels likely was due to N-glycosylation that was confirmed by lectin blots. Consistent with its surface-exposure, an antibody raised against recombinant protein stained the plasma membrane of D. discoideum amoebae. Gp130 and its transcripts were high during axenic growth of cells, but relatively low during growth on bacteria. The gene for gp130 was disrupted and cell lines lacking the glycoprotein were efficient phagocytes, indicating that gp130 was dispensable for phagocytosis. Gp130-null cells were similar in size to parent DH1 cells, had enhanced macropinocytosis and grew faster to higher densities. They also exhibited weaker cell-substrate adhesion but displayed greater cell-cell cohesion. Collectively, the data indicated that gp130 influenced macropinocytosis and played a role in adhesion during vegetative growth.
authors.affiliation: School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588-0118, USA.
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Chia
authors.forename: Sujatha
authors.initials: S
authors.lastname: Gomathinayagam
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Schmaltz
authors.forename: Laura K
authors.initials: LK
authors.lastname: Smoyer
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002448:Cell Adhesion; D002462:Cell Membrane / Q000737:chemistry; D003001:Cloning, Molecular; D004023:Dictyostelium / Q000166:cytology / Q000502:physiology*; D017125:Genes, Protozoan; D006031:Glycosylation; D007150:Immunohistochemistry; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010873:Pinocytosis; D021382:Protein Sorting Signals; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D008562:Membrane Glycoproteins; D021382:Protein Sorting Signals; D015800:Protozoan Proteins; D011994:Recombinant Proteins