Beta1-integrins mediate Ca2+-signalling and T cell spreading via divergent pathways.
Interaction of Jurkat T-lymphocytes with two extracellular matrix (ECM) proteins of the basement membrane, laminin or collagen type IV, combined with poly-L-lysine resulted in a strong adhesion, a highly increased intracellular Ca2+-concentration ([Ca2]i), as compared to cells on laminin or collagen type IV alone and in spreading of the cells. The strong adhesion was independent of an increase in [Ca2+]i, was not mediated by a beta1-integrin, and was due to charge interaction between the positively charged polyaminoacid and the negatively charged cell surface. The latter was confirmed by substitution of poly-L-lysine by other positively charged polyaminoacids. In contrast, Ca+-signalling and spreading of the cells adhering to laminin or collagen type IV combined with poly-L-lysine was completely blocked by anti-beta1 mAb. However, spreading of the cells was independent of an increase in [Ca2+]i suggesting divergent signal transduction pathways leading to Ca2+-signalling and spreading of the cells. We elucidated these signal transduction pathways by inhibition of key enzymes involved. The tyrosine kinase inhibitor genistein blocked Ca2+-signalling as well as spreading, whereas inhibitors of PKC (calphostin C, GF109203x), PLCgamma (U73122) and PLA2 (bromophenacyl-bromide (BPB), 3-[4-octadecyl)benzoyl]acrylic acid (OBAA)) selectively blocked spreading of the cells.
Schöttelndreier
H
H
University of Hamburg, Institute of Physiological Chemistry, Department of Enzyme Chemistry, Germany.
Mayr
G W
GW
Guse
A H
AH
D020013:Calcium Signaling; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement; D003094:Collagen / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism; D019169:Jurkat Cells; D007797:Laminin / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D051966:Phospholipase C gamma; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D011099:Polyglutamic Acid / Q000378:metabolism; D011107:Polylysine / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D019284:Thapsigargin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism
D004791:Enzyme Inhibitors; D019012:Integrin beta1; D007527:Isoenzymes; D007797:Laminin; D010455:Peptides; D011107:Polylysine; C015462:polyarginine; D011099:Polyglutamic Acid; C027794:polyserine; D019284:Thapsigargin; D003094:Collagen; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D010741:Phospholipases A; D054467:Phospholipases A2; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D000252:Calcium-Transporting ATPases