A dominant Jurkat T cell mutation that inhibits LFA-1-mediated cell adhesion is associated with increased cell growth.
LFA-1 exists in a low avidity state on resting leukocytes and is believed to adopt a high avidity state when the cells are exposed to a stimulus. Current evidence supports both aggregation of LFA-1 on the cell surface and conformational changes in the reversible acquisition of a high avidity state. We studied this regulation by selecting a Jurkat T cell clone, J-lo1.3, that expresses LFA-1 yet fails to bind to purified ICAM-1 despite treatment of the cells with PMA or Mn2+. Several lines of evidence demonstrated the absence of any changes within LFA-1 itself. LFA-1 protein purified from the J-lo1.3 clone and the wild-type Jurkat clone, Jn.9, were found to be functionally equivalent. The cDNA sequences encoding the LFA-1 alpha- and beta-chains from J-lo1.3 were identical with the published sequences except for nine base pairs. However, these differences were also found in a Jurkat mutant with a constitutively avid phenotype, J+hi1.19 or the wild-type Jn.9 genomic or cDNA. Fusion of J-lo1.3 with Jn.9 yielded hybrids that exhibited the J-lo1.3 adhesion phenotype, which indicated a dominant mutation in J-lo1.3. This phenotype was relatively specific for LFA-1 among all integrins expressed by Jurkat. Interestingly, the J-lo1.3 cells had a 1.2-fold faster doubling time than did the Jn.9 cells. Reversion of J-lo1.3 to the wild-type adhesion phenotype by mutagenesis and selection also decreased the growth rate. These data support a connection between cellular growth and cellular adhesion in lymphocytes.
Cherry
L K
LK
Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
Weber
K S
KS
Klickstein
L B
LB
D000818:Animals; D016466:CHO Cells; D002448:Cell Adhesion / Q000235:genetics / Q000276:immunology; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002999:Clone Cells; D006224:Cricetinae; D018076:DNA, Complementary / Q000032:analysis; D006133:Growth Substances / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D016023:Integrins / Q000037:antagonists & inhibitors / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D019169:Jurkat Cells / Q000166:cytology* / Q000276:immunology / Q000378:metabolism*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D016297:Mutagenesis, Site-Directed; D010641:Phenotype; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D017422:Sequence Analysis, DNA; D014162:Transfection; D014407:Tumor Cells, Cultured
D018076:DNA, Complementary; D006133:Growth Substances; D016023:Integrins; D016169:Lymphocyte Function-Associated Antigen-1; D018799:Intercellular Adhesion Molecule-1