Quantitative qPCR, immunoblot analysis, flow cytometry and cytochemistry were used to assess this interplay.
GABARAPL1 mRNA and protein levels are increased during hypoxia in vitro and correlate with tumor hypoxia in a panel of primary HNSCC xenografts. High GABARAPL1 mRNA is associated with poor outcome of HNSCC patients. During hypoxia, EGFR membrane expression is increased and GABARAPL1 and EGFR colocalize at the plasma membrane. GABARAPL1 knockdown inhibits EGFR membrane expression during hypoxia.
GABARAPL1 is required for increased membrane expression of EGFR during hypoxia, suggesting a role for GABARAPL1 in the trafficking of these membrane proteins.