Immunocytochemical localization of a plasma membrane calcium pump in the insect (Lymantria dispar) Malpighian tubule

Thomas L. Pannabecker, Christina A. Smith, Klaus W. Beyenbach, Robert H. Wasserman

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

The Malpighian tubules of several insects are known to secrete Ca2+ against its electrochemical potential, however the molecular identities of the Ca2+ transport pathways have not been determined. We have investigated the identity of the active transport step for calcium secretion in the larval gypsy moth Malpighian tubule, using a monoclonal antibody produced against the human erythrocyte plasma membrane calcium pump (PMCA). Western blot analysis of partially-purified cell membranes from Malpighian tubules showed that the antibody binds to a single prominent protein band with a molecular mass of approx. 143 kDa. This molecular mass is identical to that of the predominant immunoreactive protein in partially-purified membranes from the human erythrocyte. In immunocytochemical studies the anti-PMCA antibody bound predominantly to epitopes positioned along the apical domain of the transporting cells of the larval Malpighian tubule. These epitopes lie along the entire length of the tubule. A phylogenetically conserved PMCA is a likely candidate for active calcium transport across the apical membrane. Immunoreactive proteins were undetectable in Western analyses of partially-purified cell membranes from tubules of the adult gypsy moth, and immunostaining of adult tissue sections was weak or nonexistent. A reduction in immunoreactive protein density in the adult tubule may reflect structural modifications which occur late in the last larval instar or pupal stage.

Original languageEnglish (US)
Pages (from-to)1105-1112
Number of pages8
JournalJournal of Insect Physiology
Volume41
Issue number12
DOIs
StatePublished - Dec 1995

Keywords

  • Antibody 5F10
  • Calcium homeostasis
  • Diuretic hormone
  • Membrane transport

ASJC Scopus subject areas

  • Physiology
  • Insect Science

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