Oxygen sensing

HIF-α targeted for VHL-mediated destruction by proline hydroxylation: implications for O2 sensing. Ivan, M. et al. Science 292 , 464?468 (2001) [PubMed]

Targeting of HIF-α to the von Hippel?Lindau ubiquitylation complex by O2-regulated prolyl hydroxylation. Jaakkola, P. et al. Science 292 , 468?472 (2001) [PubMed]

Hypoxia-inducible factor (HIF) is a transcriptional complex that regulates gene activity in response to levels of O2 ? when O2 is present, HIF is destroyed by a complex involving the VHL protein. These papers show that the HIF?VHL interaction is regulated by hydroxylation of a proline residue on the HIF-1α subunit, suggesting that proline hydroxylation could be key in cellular responses to O2.

Development

Drosophila Rho-associated kinase (Drok) links Frizzled-mediated planar cell polarity signaling to the actin cytoskeleton. Winter, C. G. et al. Cell 105 , 81?91 (2001) [Contents page]

The Frizzled (Fz)/Dishevelled (Dsh) pathway mediates planar cell polarity. But how does it regulate cytoskeletal reorganization? Winter and colleagues now report that Drosophila Rho-associated kinase acts downstream of Fz/Dsh to phosphorylate nonmuscle myosin II and restrict F-actin bundle formation.

Technique

Attomole level protein sequencing by Edman degradation coupled with accelerator mass spectrometry. Miyashita, M. et al. Proc. Natl Acad. Sci. USA 98 , 4403?4408 (2001) [PubMed]

The limit for amino-terminal sequencing has just been pushed down to the low attomole level. The authors have increased the sensitivity of Edman sequencing by introducing accelerator mass spectrometry ? a tandem spectrometry tool that counts rare atoms ? as a detection system.

Extracellular matrix

Extracellular matrix composition determines the transcriptional response to epidermal growth factor receptor activation. Yarwood, S. J. & Woodgett, J. R. Proc. Natl Acad. Sci. USA 98 , 4472?4477 (2001) [PubMed]

Integrins transduce signals from the extracellular matrix (ECM) and modulate receptor tyrosine kinases. The authors used DNA arrays to monitor EGF-induced gene expression after attachment of cells to either laminin or fibronectin. Although expression of most genes was not influenced by the type of ECM, certain gene clusters responded differentially. This survey should be valuable for further analysis of the crosstalk between ECM and growth factor signalling.