TY - JOUR
T1 - Evidence of redox‐linked signaling for producing a giant signal complex
AU - Katano, Yoshiaki
AU - Pu, Mei‐Yi ‐Y
AU - Akhand, Anwarul Azeim
AU - Hamaguchi, Michinari
AU - Koga, Yasuhiro
AU - Isobe, Ken‐Ichi ‐I
AU - Fukuda, Yoshihide
AU - Hayakawa, Tetsuo
AU - Nakashima, Izumi
PY - 1995/3
Y1 - 1995/3
N2 - Previously we showed that a thiol‐reactive heavy metal, HgCl2, crosslinked multiple cell surface receptors through a ligand‐independent pathway, which produced massive aggregates of phosphotyrosine (PTYR)‐containing proteins beneath plasma membrane [Nakashima et al. (1994): J Immunol 152:1064–1071]. In this study we characterized these unique aggregates at the molecular level. The lysates in Brij 96 of thymocytes treated with HgCl2 were separated into the supernatant and pellet fractions by simple centrifugation. Selected PTYR‐containing proteins and p56lck appeared in the pellet fraction as quickly as 5 s after exposure to HgCl2, and were further increased in amount by 5 min. Although the mechanism of triggering these events was redox‐linked, the majority of proteins in the Brij 96‐insoluble aggregates were dissociated in SDS‐PAGE under nonreducing condition. This suggested that PTYR‐containing proteins and p56lck themselves do not form dimer or polymer directly by thiol‐mediated bond. The pellet fraction was further found to include some other signal delivery elements, such as GTPase activating protein, phosphatidylinositol 3 kinase, and mitogen‐activated protein kinase. Finally, all of these signal elements and selected PTYR‐containing proteins were collected in the same fraction by the sucrose density gradient centrifugation. These results suggest a unique redox‐linked pathway of formation of a giant signal complex.
AB - Previously we showed that a thiol‐reactive heavy metal, HgCl2, crosslinked multiple cell surface receptors through a ligand‐independent pathway, which produced massive aggregates of phosphotyrosine (PTYR)‐containing proteins beneath plasma membrane [Nakashima et al. (1994): J Immunol 152:1064–1071]. In this study we characterized these unique aggregates at the molecular level. The lysates in Brij 96 of thymocytes treated with HgCl2 were separated into the supernatant and pellet fractions by simple centrifugation. Selected PTYR‐containing proteins and p56lck appeared in the pellet fraction as quickly as 5 s after exposure to HgCl2, and were further increased in amount by 5 min. Although the mechanism of triggering these events was redox‐linked, the majority of proteins in the Brij 96‐insoluble aggregates were dissociated in SDS‐PAGE under nonreducing condition. This suggested that PTYR‐containing proteins and p56lck themselves do not form dimer or polymer directly by thiol‐mediated bond. The pellet fraction was further found to include some other signal delivery elements, such as GTPase activating protein, phosphatidylinositol 3 kinase, and mitogen‐activated protein kinase. Finally, all of these signal elements and selected PTYR‐containing proteins were collected in the same fraction by the sucrose density gradient centrifugation. These results suggest a unique redox‐linked pathway of formation of a giant signal complex.
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U2 - 10.1002/jcb.240570309
DO - 10.1002/jcb.240570309
M3 - Article
C2 - 7539434
AN - SCOPUS:0028935288
SN - 0730-2312
VL - 57
SP - 432
EP - 439
JO - Journal of Cellular Biochemistry
JF - Journal of Cellular Biochemistry
IS - 3
ER -