Plant cells contain two functionally distinct vacuolar compartments

Cell. 1996 May 17;85(4):563-72. doi: 10.1016/s0092-8674(00)81256-8.

Abstract

The plant cell vacuole has multiple functions, including storage of proteins and maintenance of an acidic pH where proteases will have maximal activity. It has been assumed that these diverse functions occur in the same compartment. Here, we demonstrate that antibodies to two different tonoplast intrinsic proteins, alpha-TIP and TIP-Ma27, label vacuole membranes of two different compartments within the same cell. These compartments are functionally distinct, because barley lectin, a protein stored in root tips, is exclusively contained within the alpha-TIP compartment, while aleurain, a protease that serves as a marker for an acidified vacuolar environment, is exclusively contained within the TIP-Ma27 compartment. As cells develop large vacuoles, the two compartments merge; this may represent a process by which storage products in the alpha-TIP compartment are exposed to the acidic lytic TIP-Ma27 compartment for degradation.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Compartmentation / physiology*
  • Cysteine Endopeptidases / analysis
  • Fluorescent Antibody Technique
  • Hordeum / cytology*
  • Membrane Proteins / analysis
  • Microscopy, Confocal
  • Peas / cytology*
  • Plant Cells
  • Plant Proteins / analysis
  • Plant Roots / cytology
  • Plant Roots / embryology
  • Vacuoles / chemistry
  • Vacuoles / enzymology
  • Vacuoles / physiology*

Substances

  • Membrane Proteins
  • Plant Proteins
  • tonoplast intrinsic protein, plant
  • alpha-TIP protein, Phaseolus vulgaris
  • Cysteine Endopeptidases
  • aleurain