Dynamic movement of the calcium sensor STIM1 and the calcium channel orai1 in activated T-cells: Puncta and distal caps

Valarie A. Barr, Kelsie M. Bernot, Sonal Srikanth, Yousang Gwack, Lakshmi Balagopalan, Carole K. Regan, Daniel J. Helman, Connie L. Sommers, Masatsugu Oh-hora, Anjana Rao, Lawrence E. Samelson

Research output: Contribution to journalArticlepeer-review

109 Citations (Scopus)

Abstract

The proteins STIM1 and Orai1 are the long sought components of the store-operated channels required in T-cell activation. However, little is known about the interaction of these proteins in T-cells after engagement of the T-cell receptor. We found that T-cell receptor engagement caused STIM1 and Orai1 to colocalize in puncta near the site of stimulation and accumulate in a dense structure on the opposite side of the T-cell. FRET measurements showed a close interaction between STIM1 and Orai1 both in the puncta and in the dense cap-like structure. The formation of cap-like structures did not entail rearrangement of the entire endoplasmic reticulum. Cap formation depended on TCR engagement and tyrosine phosphorylation, but not on channel activity or Ca2+ influx. These caps were very dynamic in T-cells activated by contact with superantigen pulsed B-cells and could move from the distal pole to an existing or a newly forming immunological synapse. One function of this cap may be to provide preassembled Ca2+ channel components to existing and newly forming immunological synapses.

Original languageEnglish
Pages (from-to)2802-2817
Number of pages16
JournalMolecular biology of the cell
Volume19
Issue number7
DOIs
Publication statusPublished - Jul 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

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