Characterization of prominin-2, a new member of the prominin family of pentaspan membrane glycoproteins

J Biol Chem. 2003 Mar 7;278(10):8586-96. doi: 10.1074/jbc.M210640200. Epub 2003 Jan 3.

Abstract

Prominin/CD133 is a 115/120-kDa integral membrane glycoprotein specifically associated with plasma membrane protrusions in epithelial and non-epithelial cells including neuroepithelial and hematopoietic stem cells. Here we report the identification as well as molecular and cell biological characterization of mouse, rat, and human prominin-2, a 112-kDa glycoprotein structurally related to prominin (referred to as prominin-1). Although the amino acid identity between prominin-2 and prominin-1 is low (<30%), their genomic organization is strikingly similar, suggesting an early gene duplication event. Like prominin-1, prominin-2 exhibits a characteristic membrane topology with five transmembrane segments and two large glycosylated extracellular loops. Upon its ectopic expression in Chinese hamster ovary cells as a green fluorescent protein fusion chimera, prominin-2 was also found to be associated with plasma membrane protrusions, as revealed by its co-localization with prominin-1, suggesting a related role. Consistent with this, prominin-2 shows a similar tissue distribution to prominin-1, being highly expressed in the adult kidney and detected all along the digestive tract as well as in various other epithelial tissues. However, in contrast to prominin-1, prominin-2 was not detected in the eye, which perhaps explains why a loss-of function mutation in the human prominin-1 gene causes retinal degeneration but no other obvious pathological signs. Finally, we present evidence for the existence of a family of pentaspan membrane proteins, the prominins, which are conserved in evolution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cloning, Molecular
  • DNA, Complementary
  • Expressed Sequence Tags
  • Eye / metabolism
  • Humans
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Mice
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • RNA, Messenger / genetics
  • Rats
  • Sequence Homology, Amino Acid

Substances

  • DNA, Complementary
  • Membrane Glycoproteins
  • PROM2 protein, human
  • Prom2 protein, mouse
  • Prom2 protein, rat
  • RNA, Messenger

Associated data

  • GENBANK/AF127935
  • GENBANK/AF128113
  • GENBANK/AF160970
  • GENBANK/AF197345
  • GENBANK/AF245303
  • GENBANK/AF245304
  • GENBANK/AF269062
  • GENBANK/AF373869
  • GENBANK/AF406812
  • GENBANK/AF508942