Use the actin-binding domain of Utrophin as a probe for actin filaments

This GFP-UtrCH probe was published earlier than the 17aa peptide LifeAct (PMID: 18536722). Someone told me that it is better than LifeAct. I have not tested it myself. It would be interesting to compare LifeAct with UtrCH. We know that LifeAct cannot label certain actin stress fibers (PMID: 19404250). What is the limitation of UtrCH?

The size of the domain is about 161aa, which is OK size as a probe. The sequences are

>gi|110611227:93-875 Homo sapiens utrophin (UTRN), mRNA
ATGGCCAAGTATGGAGAACATGAAGCCAGTCCTGACAATGGGCAGAACGAATTCAGTGATATCATTAAGT
CCAGATCTGATGAACACAATGACGTACAGAAGAAAACCTTTACCAAATGGATAAATGCTCGATTTTCAAA
GAGTGGGAAACCACCCATCAATGATATGTTCACAGACCTCAAAGATGGAAGGAAGCTATTGGATCTTCTA
GAAGGCCTCACAGGAACATCACTGCCAAAGGAACGTGGTTCCACAAGGGTACATGCCTTAAATAACGTCA
ACAGAGTGCTGCAGGTTTTACATCAGAACAATGTGGAATTAGTGAATATAGGGGGAACTGACATTGTGGA
TGGAAATCACAAACTGACTTTGGGGTTACTTTGGAGCATCATTTTGCACTGGCAGGTGAAAGATGTCATG
AAGGATGTCATGTCGGACCTGCAGCAGACGAACAGTGAGAAGATCCTGCTCAGCTGGGTGCGTCAGACCA
CCAGGCCCTACAGCCAAGTCAACGTCCTCAACTTCACCACCAGCTGGACAGATGGACTCGCCTTTAATGC
TGTCCTCCACCGACATAAACCTGATCTCTTCAGCTGGGATAAAGTTGTCAAAATGTCACCAATTGAGAGA
CTTGAACATGCCTTCAGCAAGGCTCAAACTTATTTGGGAATTGAAAAGCTGTTAGATCCTGAAGATGTTG
CCGTTCAGCTTCCTGACAAGAAATCCATAATTATGTATTTAACATCTTTGTTTGAGGTGCTACCTCAGCA
AGTCACCATAGAC
>translated aa sequence
MAKYGEHEASPDNGQNEFSDIIKSRSDEHNDVQKKTFTKWINARFSKSGKPPINDMFTDL
KDGRKLLDLLEGLTGTSLPKERGSTRVHALNNVNRVLQVLHQNNVELVNIGGTDIVDGNH
KLTLGLLWSIILHWQVKDVMKDVMSDLQQTNSEKILLSWVRQTTRPYSQVNVLNFTTSWT
DGLAFNAVLHRHKPDLFSWDKVVKMSPIERLEHAFSKAQTYLGIEKLLDPEDVAVQLPDK
KSIIMYLTSLFEVLPQQVTID

Cell Motil Cytoskeleton. 2007 Nov;64(11):822-32.

Versatile fluorescent probes for actin filaments based on the actin-binding domain of utrophin.

Burkel BM, von Dassow G, Bement WM.

Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin, USA.

Actin filaments (F-actin) are protein polymers that undergo rapid assembly and disassembly and control an enormous variety of cellular processes ranging from force production to regulation of signal transduction. Consequently, imaging of F-actin has become an increasingly important goal for biologists seeking to understand how cells and tissues function. However, most of the available means for imaging F-actin in living cells suffer from one or more biological or experimental shortcomings. Here we describe fluorescent F-actin probes based on the calponin homology domain of utrophin (Utr-CH), which binds F-actin without stabilizing it in vitro. We show that these probes faithfully report the distribution of F-actin in living and fixed cells, distinguish between stable and dynamic F-actin, and have no obvious effects on processes that depend critically on the balance of actin assembly and disassembly. (c) 2007 Wiley-Liss, Inc.

PMID: 17685442