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Updated: Jul 13, 2026
Differentiation, Maintenance, and Analysis of Human Retinal Pigment Epithelium Cells: A Disease-in-a-dish Model for BEST1 Mutations
Published on: August 24, 2018
Hop/STI1 modulates retinal proliferation and cell death independent of PrPC
Maithe Arruda-Carvalho1, Brian Njaine, Mariana S Silveira
1Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Biofísica da UFRJ, Centro de Ciências da Saúde, bloco G, G2-019 Cidade Universitária, 21941-902, Rio de Janeiro, Brazil.
Abstract:
Hop/STI1 is a co-chaperone adaptor protein for Hsp70/Hsp90 complexes. Hop/STI1 is found extracellularly and modulates cell death and differentiation through interaction with the prion protein (PrP(C)). Here, we investigated the expression of hop/STI1 and its role upon cell proliferation and cell death in the developing retina. Hop/STI1 is more expressed in developing rat retina than in the mature tissue. Hop/STI1 blocks retinal cell death in the neuroblastic layer (NBL) in a PrP(C) dependent manner, but failed to protect ganglion cells against axotomy-induced cell death. An antibody raised against hop/STI1 (alpha-STI1) blocked both ganglion cell and NBL cell death independent of PrP(C). cAMP/PKA, ERK, PI3K and PKC signaling pathways were not involved in these effects. Hop/STI1 treatment reduced proliferation, while alpha-STI1 increased proliferation in the developing retina, both independent of PrP(C). We conclude that hop/STI1 can modulate both proliferation and cell death in the developing retina independent of PrP(C).
