PKmito Probes in Action

Mitochondria and Microproteins

During initial efforts to annotate genomes, many potential coding sequences were identified that were assumed to be too short to encode functional proteins. To reduce the number of annotations and reduce the risk of false positives, an arbitrary cutoff was therefore applied, and sequences shorter than 100 amino acids (aa) were filtered out.1 Later, it was discovered that many of these small open reading frames (smORFs) are translated to produce microproteins, or micropeptides, whose expression is apparently just as tightly controlled as for canonical proteins.1,2
Many microproteins are encoded in 5'-untranslated regions (5'-UTRs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), and a significant number of them are translated from non-AUG start codons.3,4 These features traditionally made them difficult to identify, but the use of modern genomics technologies, such as ribosome profiling (Ribo-Seq) and sensitive proteomics workflows, has now firmly established that many smORFs are translated to produce detectable microproteins. Multiple studies have identified hundreds of microproteins in various cell types and tissues,4–6 often including previously unannotated examples, but the function of most of them remains unknown. Nevertheless, the emerging evidence indicates key roles for microproteins in many cellular and physiological processes, and in this newsletter, we will review some of the most important findings so far. 

Mitochondria (false green colored) labeled with PKmito Deep Red. video courtesy of Prof. Simon Watkins, University of Pittsburgh, PA, USA


That pk mito 640 probe is exceptional.  Following  reasons.  VERY bright.  I was using an NSPARC detector with zero integration in resonant scan mode in 3D, one Z stack collected every 10 seconds for an hour to collect the data in these movies.  There is no bleaching. 

The impact of this is really important because the laser power was so low there was no photo toxicity issues (ie no mito fragmentation etc… none of the silly “heizenbergian” problems of disturbing mitos with light (beading etc) when collecting.. quite impressive.  

Top 15 Medical Research Institute -- Prof. Simon Watkins, University of Pittsburgh, PA, USA

Recent PKmito Citations

Chen Q. et al. 2023. Mitochondrial nucleoid condensates drive peripheral fission through high membrane curvature. Cell Reports.


Cytoskeleton's Newest PKmito Tool - PKmito Orange FX 

Z-stack STED images of mitochondrial cristae (STED, grey) and nascent DNA (confocal, green) in a HeLa cell labeled with PKMO FX and Click-iTTM AF488. Chen J. et al PNAS 2024. 121 (19) e2317703121

PKmito Orange FX Probe (Cat. # CY-SC054)

PKmito Orange FX labels mitochondria in formaldehyde (FA) or glutaraldehyde (GA) fixed cells with very high specificity. The unique and unmatched feature of PKmito Orange FX is its ability to be retained nearly quantitatively after aldehyde fixation of stained cells. PKmito Orange FX is extremely well suited for STED and SIM superresolution imaging.