Interference with Ca(2+) release activated Ca(2+) (CRAC) channel function delays T-cell arrest in vivo.
Entry of lymphocytes into secondary lymphoid organs (SLOs) involves intravascular arrest and intracellular calcium ion ([Ca(2+)]i) elevation. TCR activation triggers increased [Ca(2+)]i and can arrest T-cell motility in vitro. However, the requirement for [Ca(2+)]i elevation in arresting T cells in vivo has not been tested. Here, we have manipulated the Ca(2+) release-activated Ca(2+) (CRAC) channel pathway required for [Ca(2+)]i elevation in T cells through genetic deletion of stromal interaction molecule (STIM) 1 or by expression of a dominant-negative ORAI1 channel subunit (ORAI1-DN). Interestingly, the absence of CRAC did not interfere with homing of naïve CD4(+) T cells to SLOs and only moderately reduced crawling speeds in vivo. T cells expressing ORAI1-DN lacked TCR activation induced [Ca(2+)]i elevation, yet arrested motility similar to control T cells in vitro. In contrast, antigen-specific ORAI1-DN T cells had a twofold delayed onset of arrest following injection of OVA peptide in vivo. CRAC channel function is not required for homing to SLOs, but enhances spatiotemporal coordination of TCR signaling and motility arrest.
Program in Molecular Pathogenesis, Helen L. and Martin S. Kimmel Center for Biology and Medicine of the Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA.
Janelle C
JC
Waite
Santosh
S
Vardhana
Patrick J
PJ
Shaw
Jung-Eun
JE
Jang
Christie-Ann
CA
McCarl
Thomas O
TO
Cameron
Stefan
S
Feske
Michael L
ML
Dustin
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002118:Calcium / Q000276:immunology*; D015220:Calcium Channels / Q000235:genetics / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D000071740:ORAI1 Protein; D010455:Peptides / Q000276:immunology / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology; D000071737:Stromal Interaction Molecule 1
D015220:Calcium Channels; D008562:Membrane Glycoproteins; D000071740:ORAI1 Protein; C520430:Orai1 protein, mouse; D010455:Peptides; D011948:Receptors, Antigen, T-Cell; C100757:Stim1 protein, mouse; D000071737:Stromal Interaction Molecule 1; D002118:Calcium
Antigen recognition; Calcium signaling; Intravital microscopy; T‐cell activation