Hypoxia-inducible factor alpha (HIF-1α) is stabilized under hypoxia but remains in the cytoplasm. (A) Scheme of sample acquisition for kinetic analyzes of monocytes incubated in a water-jacket chamber sealed with a Clark-type oxygen electrode, which facilitates the constant monitoring of oxygen saturation during the experimental setup (sample acquisition is indicated by arrows). (B) Detection of HIF-1α and, for normalization purposes, β-actin in monocyte whole cell protein samples acquired as shown in (A) by immunoblot. Under hypoxia, monocytes stabilize HIF-1α in a time-dependent manner. (C) Detection of HIF-1α, β-actin and for normalization purposes, the nuclear protein Lamin B, in monocyte nuclear fraction (NF+) and cytosolic (NF-) cell fractions using immunoblot. HIF-1α was exclusively detected in the cytoplasm in unstimulated monocytes incubated under hypoxic conditions (n = 6).
Fangradt et al. Arthritis Research & Therapy 2012 14:R181 doi:10.1186/ar4011