Predominant Expression of Hybrid N-Glycans Has Distinct Cellular Roles Relative to Complex and Oligomannose N-Glycans

Int J Mol Sci. 2016 Jun 13;17(6):925. doi: 10.3390/ijms17060925.

Abstract

Glycosylation modulates growth, maintenance, and stress signaling processes. Consequently, altered N-glycosylation is associated with reduced fitness and disease. Therefore, expanding our understanding of N-glycans in altering biological processes is of utmost interest. Herein, clustered regularly interspaced short palindromic repeats/caspase9 (CRISPR/Cas9) technology was employed to engineer a glycosylation mutant Chinese Hamster Ovary (CHO) cell line, K16, which expresses predominantly hybrid type N-glycans. This newly engineered cell line enabled us to compare N-glycan effects on cellular properties of hybrid type N-glycans, to the well-established Pro(-)5 and Lec1 cell lines, which express complex and oligomannose types of N-glycans, respectively. Lectin binding studies revealed the predominant N-glycan expressed in K16 is hybrid type. Cell dissociation and migration assays demonstrated the greatest strength of cell-cell adhesion and fastest migratory rates for oligomannose N-glycans, and these properties decreased as oligomannose type were converted to hybrid type, and further decreased upon conversion to complex type. Next, we examined the roles of three general types of N-glycans on ectopic expression of E-cadherin, a cell-cell adhesion protein. Microscopy revealed more functional E-cadherin at the cell-cell border when N-glycans were oligomannose and these levels decreased as the oligomannose N-glycans were processed to hybrid and then to complex. Thus, we provide evidence that all three general types of N-glycans impact plasma membrane architecture and cellular properties.

Keywords: N-glycan; cadherin; cell motility; cell surface glycan; cell–cell adhesion; glycobiology; lateral heterogeneity of proteins in membranes; transmembrane glycoprotein.

MeSH terms

  • Acyltransferases / genetics
  • Acyltransferases / metabolism
  • Animals
  • CHO Cells
  • Cadherins / metabolism
  • Cell Adhesion
  • Cell Membrane / metabolism
  • Cell Movement
  • Cricetinae
  • Cricetulus
  • Gene Knockout Techniques
  • Glycosylation
  • Lectins / metabolism
  • Mannose / metabolism*
  • Membrane Proteins / metabolism
  • Polysaccharides / metabolism*
  • Protein Binding
  • Protein Transport

Substances

  • Cadherins
  • Lectins
  • Membrane Proteins
  • Polysaccharides
  • Acyltransferases
  • 2-acylglycerol O-acyltransferase
  • Mannose