An apparently novel protein of human leukocytes, reactive with an antibody to protein kinase C-gamma, is rapidly modified upon cell activation: initial characterization in neutrophils and their cytoplasts.
On immunoblots of human neutrophil cytoplasts (U-CYT), a previously undescribed 97 kDa protein was revealed by intense and selective reaction with an antibody that was initially raised to recognize PKC-gamma. Denoted "gamma-rp" for gamma-related protein, this acidic cytosolic protein somewhat resembled the classic forms of PKC in several biochemical respects. Appearing as a doublet on low-percentage SDS-PAGE gels, both its mobility and staining pattern were rapidly altered by treatment of U-CYT with either phorbol ester or chemotactic peptide. Whole neutrophil gamma-rp was detectable only after TCA precipitation of intact cells. It was also detectable in human platelets, lymphocytes, and neutrophil-like differentiated HL60 cells, but not in fibroblasts, erythrocytes, monocytes, or monocyte-like differentiated HL60 cells. Our data suggest that gamma-rp merits further study as a potential participant in cellular activation, and as a possible structural or functional relative of PKC.
Smallwood
J I
JI
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8031, USA.
Malawista
S E
SE
D000293:Adolescent; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001792:Blood Platelets / Q000737:chemistry; D001798:Blood Proteins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification*; D002847:Chromatography, Agarose; D002848:Chromatography, DEAE-Cellulose; D003600:Cytosol / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D018922:HL-60 Cells; D006801:Humans; D015151:Immunoblotting; D007527:Isoenzymes / Q000737:chemistry / Q000276:immunology*; D008214:Lymphocytes / Q000737:chemistry; D018375:Neutrophil Activation; D009504:Neutrophils / Q000737:chemistry* / Q000502:physiology; D011493:Protein Kinase C / Q000737:chemistry / Q000276:immunology*; D013329:Structure-Activity Relationship; D014462:Ultrafiltration
D000906:Antibodies; D001798:Blood Proteins; D007527:Isoenzymes; C087857:protein kinase C gamma; D011493:Protein Kinase C