HIF-1 Alpha

Hypoxia Inducible Factor 1 Alpha (HIF-1 Alpha) is a transcription factor. It is oxygen dependent which means it is sensitive to the levels of oxygen a cell is exposed to.  When oxygen is present, HIF-1 Alpha is hydroxylated by prolyl hydroxylases. These hydroxylations target HIF-1 Alpha for ubiquitination. The presence of ubiquitinations result in HIF-1 Alpha degradation by proteasomes.


When cells are under hypoxic conditions, no hydroxylation of HIF-1 Alpha occurs reulting in no degradation of HIF-1 Alpha. This means that HIF-1 Alpha can build up in the cell. HIF-1 Alpha then binds to a nuclear translocator, ARNT, and enters the nucleus. Once inside the nucleus, the ARNT and HIF-1 Alpha complex, called HIF-1, allows for the transcription of target genes. These target genes allow for cellular survival in hypoxia.


Some of this mechanism can be seen in the image below from http://journals.cambridge.org/fulltext_content/ERM/ERM7_06/S1462399405009117sup010.gif

To learn more about HIF-1 Alpha, visit:

http://en.wikipedia.org/wiki/Hypoxia-inducible_factors 

http://www.ncbi.nlm.nih.gov/protein?Db=gene&term=(hif1%20alpha[gene])%20AND%20(Homo%20sapiens[orgn])%20AND%20alive[prop]%20NOT%20newentry[gene]&sort=weight 

http://www.e-emm.org/search_read.htm?page=1&year=2004&vol=36