Ectodomain shedding, translocation and synthesis of SorLA are stimulated by its ligand head activator.
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Ectodomain shedding, translocation and synthesis of SorLA are stimulated by its ligand head activator. / Hampe, Wolfgang; Riedel, I B; Lintzel, J; Bader, C O; Franke, I; Schaller, H C.
In: J CELL SCI, Vol. 113, No. 24, 24, 2000, p. 4475-4485.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - Ectodomain shedding, translocation and synthesis of SorLA are stimulated by its ligand head activator.
AU - Hampe, Wolfgang
AU - Riedel, I B
AU - Lintzel, J
AU - Bader, C O
AU - Franke, I
AU - Schaller, H C
PY - 2000
Y1 - 2000
N2 - The single transmembrane receptor SorLA is the mammalian orthologue of the head activator-binding protein, HAB, from hydra. The human neuronal precursor cell line NT2 and the neuroendocrine cell line BON produce head activator (HA) and respond to HA by entry into mitosis and cell proliferation. They express SorLA, and bind HA with nanomolar affinity. HA coupled to Sepharose is able to precipitate SorLA specifically proving that SorLA binds HA. Using antisera directed against extra- and intracellular epitopes we find SorLA as membrane receptor and as soluble protein released from cells into the culture medium. Cell lines differ strongly in processing of SorLA, with NT2 cells expressing SorLA mainly as membrane receptor, whereas release predominates in BON cells. Soluble SorLA lacks the intracellular domain and is shed from the transmembrane protein by a metalloprotease. Release from cells and brain slices is stimulated by HA and by phorbol ester, and it is blocked by a metalloprotease inhibitor and by lowering the temperature to 20 degrees C. Blockade of SorLA shedding and treatment of cells with SorLA antisense oligonucleotides lead to a decrease in the rate of cell proliferation. From this we conclude that SorLA is necessary to mediate the mitogenic effect of endogenous HA. HA enhances the translocation of SorLA from internal membranes to the cell surface and its internalization. In addition, HA stimulates SorLA synthesis hinting at an autocatalytic feedback loop in which the ligand activates production, processing, and translocation of its receptor.
AB - The single transmembrane receptor SorLA is the mammalian orthologue of the head activator-binding protein, HAB, from hydra. The human neuronal precursor cell line NT2 and the neuroendocrine cell line BON produce head activator (HA) and respond to HA by entry into mitosis and cell proliferation. They express SorLA, and bind HA with nanomolar affinity. HA coupled to Sepharose is able to precipitate SorLA specifically proving that SorLA binds HA. Using antisera directed against extra- and intracellular epitopes we find SorLA as membrane receptor and as soluble protein released from cells into the culture medium. Cell lines differ strongly in processing of SorLA, with NT2 cells expressing SorLA mainly as membrane receptor, whereas release predominates in BON cells. Soluble SorLA lacks the intracellular domain and is shed from the transmembrane protein by a metalloprotease. Release from cells and brain slices is stimulated by HA and by phorbol ester, and it is blocked by a metalloprotease inhibitor and by lowering the temperature to 20 degrees C. Blockade of SorLA shedding and treatment of cells with SorLA antisense oligonucleotides lead to a decrease in the rate of cell proliferation. From this we conclude that SorLA is necessary to mediate the mitogenic effect of endogenous HA. HA enhances the translocation of SorLA from internal membranes to the cell surface and its internalization. In addition, HA stimulates SorLA synthesis hinting at an autocatalytic feedback loop in which the ligand activates production, processing, and translocation of its receptor.
M3 - SCORING: Zeitschriftenaufsatz
VL - 113
SP - 4475
EP - 4485
JO - J CELL SCI
JF - J CELL SCI
SN - 0021-9533
IS - 24
M1 - 24
ER -