Signalling processes involved in C-peptide-induced chemotaxis of CD4-positive lymphocytes.
Previous data from our group demonstrated that C-peptide induces chemotaxis of CD4-positive lymphocytes in-vitro, mediated by activation of G-protein and PI 3-kinase gamma, but additional signalling pathways involved in this process remained unexplored. In the present study we further analyze intracellular signalling pathways which lead to C-peptide-induced CD4-positive lymphocyte migration. We provide evidence that C-peptide-induced chemotaxis of CD4-positive lymphocytes is critically dependent on activation of Src-kinase and RhoA, Rac-1 and Cdc42 GTPases. Furthermore, C-peptide stimulates phosphorylation of PAK, LIMK and cofilin downstream of Rac-1 and Cdc42, leading to cofilin inactivation and actin filament stabilization. In addition, C-peptide induces ROCK kinase activity and MLC phosphorylation downstream of RhoA, thereby stimulating myosin mediated cell contraction. In contrast, C-peptide does not activate ERK1/2, p38 or Akt in CD4-positive lymphocytes. Our data support an active role of C-peptide in CD4-positive lymphocyte chemotaxis and elucidate molecular mechanisms in C-peptide-induced cell migration.
Department of Internal Medicine II - Cardiology, University of Ulm, Robert Koch Str. 8, D-89081, Ulm, Germany.
M
M
Aleksic
D
D
Walcher
K
K
Giehl
H
H
Bach
M
M
Grüb
R
R
Durst
V
V
Hombach
N
N
Marx
D008841:Actin Cytoskeleton / Q000378:metabolism; D002096:C-Peptide / Q000494:pharmacology* / Q000502:physiology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation; D006801:Humans; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology*
D002096:C-Peptide