The cytoskeleton-associated TCR ζ chain is constitutively phosphorylated in the absence of an active p56lck form

Steve Caplan, Osnat Almogi-Hazan, Anala Ezernitchi, Efrat Manaster, Aviv Gazit, Michal Baniyash

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The TCR recognizes peptide-MHC complexes and transmits activation signals leading to cellular responses. We have previously characterized two TCR populations expressed on the T cell surface; one is linked to the cytoskeleton via a detergent-insoluble cytoskeleton-associated ζ (cska-ζ) chain, while the other is detergent soluble and not linked to the cytoskeleton. The cska-ζ form displays unique properties: it is constitutively phosphorylated, does not undergo hyperphosphorylation upon TCR stimulation as opposed to its non-cytoskeleton-associated counterpart (non-cska-ζ) and it maintains a molecular mass of 16 kDa. It is well established that p56lck and possibly p59fyn are responsible for the generation of the 21/23-kDa phosphorylated detergent-soluble ζ form. We now demonstrate that the posphorylation of cska-ζ does not require the activity of p56lck. We also show that although Lck does not phosphorylate cska-ζ in vivo, it retains the capacity to phosphorylate cska-ζ in vitro. Moreover, differences in ζ-associated kinase activity were detected for non-cska-ζ and cska-ζ. Our results indicating that different kinases phosphorylate the two ζ forms are consistent with a growing consensus that each TCR form may regulate distinct cellular functions.

Original languageEnglish (US)
Pages (from-to)580-589
Number of pages10
JournalEuropean Journal of Immunology
Issue number2
StatePublished - 2001
Externally publishedYes


  • Cytoskeleton
  • Signaling
  • T cell
  • TCR

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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