hnRNP K: one protein multiple processes.
Since its original identification as a component of the heterogeneous nuclear ribonucleoprotein (hnRNP) complex, K protein has been found not only in the nucleus but also in the cytoplasm and mitochondria and is implicated in chromatin remodeling, transcription, splicing and translation processes. K protein contains multiple modules that, on one hand, bind kinases while, on the other hand, recruit chromatin, transcription, splicing and translation factors. Moreover, the K- protein-mediated interactions are regulated by signaling cascades. These observations are consistent with K protein acting as a docking platform to integrate signaling cascades by facilitating cross-talk between kinases and factors that mediate nucleic-acid-directed processes. Comparison of K across species reveals that it is an essential factor in metazoans, but not in yeast. Although some of the K protein interactions and functions are conserved in eukaryotes from yeast to man, the mammalian protein seems to play a wider role. The greater diversity of mammalian K protein interactions and function may reflect gain of novel docking sites and expansion evolutionary of gene expression networks.
Bomsztyk
Karol
K
Department of Medicine, University of Washington, Seattle, WA 98195, USA. karolb@u.washington.edu
Denisenko
Oleg
O
Ostrowski
Jerzy
J
D017398:Alternative Splicing; D000818:Animals; D002843:Chromatin / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005786:Gene Expression Regulation; D034641:Heterogeneous-Nuclear Ribonucleoprotein K / Q000737:chemistry* / Q000502:physiology*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D008957:Models, Genetic; D014176:Protein Biosynthesis; D011487:Protein Conformation; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic
D002843:Chromatin; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D012333:RNA, Messenger; D012313:RNA