title: Non-overlapping functions of Nck1 and Nck2 adaptor proteins in T cell activation.
abstract: BACKGROUND
  Signalling by the T cell antigen receptor (TCR) results in the activation of T lymphocytes. Nck1 and Nck2 are two highly related adaptor proteins downstream of the TCR that each contains three SH3 and one SH2 domains. Their individual functions and the roles of their SH3 domains in human T cells remain mostly unknown.
  
  
  RESULTS
  Using specific shRNA we down-regulated the expression of Nck1 or Nck2 to approximately 10% each in Jurkat T cells. We found that down-regulation of Nck1 impaired TCR-induced phosphorylation of the kinases Erk and MEK, activation of the AP-1 and NFAT transcription factors and subsequently, IL-2 and CD69 expression. In sharp contrast, down-regulation of Nck2 hardly impacts these activation read-outs. Thus, in contrast to Nck2, Nck1 is a positive regulator for TCR-induced stimulation of the Erk pathway. Mutation of the third SH3 domain of Nck1 showed that this domain was required for this activity. Further, TCR-induced NFAT activity was reduced in both Nck1 and Nck2 knock-down cells, showing that both isoforms are involved in NFAT activation. Lastly, we show that neither Nck isoform is upstream of p38 phosphorylation or Ca2+influx.
  
  
  CONCLUSIONS
  In conclusion, Nck1 and Nck2 have non-redundant roles in human T cell activation in contrast to murine T cells.
authors.forename: Jatuporn
authors.initials: J
authors.lastname: Ngoenkam
authors.forename: Pussadee
authors.initials: P
authors.lastname: Paensuwan
authors.forename: Kanlaya
authors.initials: K
authors.lastname: Preechanukul
authors.forename: Boonruang
authors.initials: B
authors.lastname: Khamsri
authors.forename: Ichaya
authors.initials: I
authors.lastname: Yiemwattana
authors.forename: Esmeralda
authors.initials: E
authors.lastname: Beck-García
authors.forename: Susana
authors.initials: S
authors.lastname: Minguet
authors.forename: Wolfgang W A
authors.initials: WW
authors.lastname: Schamel
authors.affiliation: Centre of Excellence in Medical Biotechnology (CEMB), Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand. sutatipp@nu.ac.th.
authors.forename: Sutatip
authors.initials: S
authors.lastname: Pongcharoen
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism; D019169:Jurkat Cells; D037181:Lectins, C-Type / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation; D020935:MAP Kinase Signaling System; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism; D015513:Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D000099192:CD69 Antigens
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D007376:Interleukin-2; D037181:Lectins, C-Type; D050778:NFATC Transcription Factors; D015513:Oncogene Proteins; D011948:Receptors, Antigen, T-Cell; D018808:Transcription Factor AP-1; D000099192:CD69 Antigens; C485544:NCK2 protein, human; C078332:Nck protein