CMT-linked loss-of-function mutations in GDAP1 impair store-operated Ca2+ entry-stimulated respiration

Sci Rep. 2017 Feb 21:7:42993. doi: 10.1038/srep42993.

Abstract

GDAP1 is an outer mitochondrial membrane protein involved in Charcot-Marie-Tooth (CMT) disease. Lack of GDAP1 gives rise to altered mitochondrial networks and endoplasmic reticulum (ER)-mitochondrial interactions resulting in a decreased ER-Ca2+ levels along with a defect on store-operated calcium entry (SOCE) related to a misallocation of mitochondria to subplasmalemmal sites. The defect on SOCE is mimicked by MCU silencing or mitochondrial depolarization, which prevent mitochondrial calcium uptake. Ca2+ release from de ER and Ca2+ inflow through SOCE in neuroblastoma cells result in a Ca2+-dependent upregulation of respiration which is blunted in GDAP1 silenced cells. Reduced SOCE in cells with CMT recessive missense mutations in the α-loop of GDAP1, but not dominant mutations, was associated with smaller SOCE-stimulated respiration. These cases of GDAP1 deficiency also resulted in a decreased ER-Ca2+ levels which may have pathological implications. The results suggest that CMT neurons may be under energetic constraints upon stimulation by Ca2+ mobilization agonists and point to a potential role of perturbed mitochondria-ER interaction related to energy metabolism in forms of CMT caused by some of the recessive or null mutations of GDAP1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / metabolism*
  • Calcium Channels / chemistry
  • Calcium Channels / genetics
  • Calcium Channels / metabolism*
  • Cell Line, Tumor
  • Charcot-Marie-Tooth Disease / genetics
  • Charcot-Marie-Tooth Disease / pathology
  • Endoplasmic Reticulum / metabolism
  • HEK293 Cells
  • Humans
  • Mitochondria / metabolism
  • Mutation, Missense
  • Nerve Tissue Proteins / antagonists & inhibitors
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Oligomycins / pharmacology
  • Oxygen Consumption / drug effects
  • RNA Interference
  • RNA, Small Interfering / metabolism

Substances

  • Calcium Channels
  • GDAP protein
  • Nerve Tissue Proteins
  • Oligomycins
  • RNA, Small Interfering
  • mitochondrial calcium uniporter
  • Calcium