The endoplasmic reticulum: one continuous or several separate Ca(2+) stores?
The Ca2+ store and sink in the endoplasmic reticulum (ER) is important for Ca2+ signal integration and for conveyance of information in spatial and temporal domains. Textbooks regard the ER as one continuous network, but biochemical and biophysical studies revealed apparently discrete ER Ca2+ stores. Recent direct studies of ER lumenal Ca2+ movements show that this organelle system is one continuous Ca2+ store, which can function as a Ca2+ tunnel. The concept of a fully connected ER network is entirely compatible with evidence indicating that the distribution of Ca2+ -release channels in the ER membrane is discontinuous with clustering in certain localities.
Petersen
O H
OH
The MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, Liverpool, UK, L69 3BX. o.h.petersen@liv.ac.uk
Tepikin
A
A
Park
M K
MK
D002118:Calcium / Q000378:metabolism*; D002451:Cell Compartmentation / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000378:metabolism*
D002118:Calcium