Expression and phosphorylation of BiP/GRP78, a molecular chaperone in the endoplasmic reticulum, during the differentiation of a mouse myeloblastic cell line.
To determine the functional significance of endoplasmic reticulum chaperones in hematopoietic cells, we analyzed the expression and post-translational modification of BiP/GRP78 and GRP94 as well as the cytoplasmic chaperones HSP70 and HSC70 during the differentiation of a mouse myeloid leukemia cell line, M1. The amounts of BiP/GRP78 and GRP94 increased several-fold when M1 cells were induced to differentiate into macrophage-like cells by treatment with interleukin-6 (IL-6). Synthesis began to increase at 4 hr after IL-6 treatment. The phosphorylated form of BiP/GRP78 increased during the later stages of differentiation. These data suggested that the chaperone activity of BiP/GRP78 and GRP94 may be needed for differentiated macrophage-like cells or for the differentiation event itself, and that functionally different BiP/GRP78 accumulate during the differentiation of M1 cells.
Nakai
A
A
Department of Cell Biology, Kyoto University, Japan.
Kawatani
T
T
Ohi
S
S
Kawasaki
H
H
Yoshimori
T
T
Tashiro
Y
Y
Miyata
Y
Y
Yahara
I
I
Satoh
M
M
Nagata
K
K
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002461:Cell Line, Transformed; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000737:chemistry; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis* / Q000737:chemistry; D015850:Interleukin-6 / Q000494:pharmacology; D007951:Leukemia, Myeloid / Q000378:metabolism* / Q000473:pathology; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018832:Molecular Chaperones / Q000096:biosynthesis / Q000737:chemistry; D010766:Phosphorylation
D000091342:Endoplasmic Reticulum Chaperone BiP; D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins; C000717248:Hspa5 protein, mouse; D015850:Interleukin-6; C060153:KAR2 protein, yeast; D018832:Molecular Chaperones