Recent in vivo studies demonstrated that aging gastric mucosa has impaired angiogenesis and reduced expression of vascular endothelial growth factor (VEGF). Angiogenesis is triggered by hypoxia and VEGF gene activation, and the latter requires transport of transcription factor(s) into endothelial cell nuclei. We focused on gastric mucosal endothelial cells (GMEC), which are key targets and effe...

1996) and the KNS shuttling domain of the hnRNP K * Zentrum fü r Molekulare Biologie der protein, which allows both import and export (Michael Universitä t Heidelberg et al., 1997). 69120 Heidelberg A fundamental question is how it is possible for the Federal Republic of Germany shuttling transport receptors to carry their cargo in only † Abteilung Molekulare Biologie der Mitose one direction. ...

Nuclear import of some viral proteins depends on importin a proteins. However, no preferences of distinct a-importins for any viral protein import have been demonstrated. We used in vitro import assays and observed that all ubiquitously expressed human importin a isoforms mediate nuclear translocation of adenoviral E1A. Competition with nucleoplasmin suggests that importin a3 is the most effici...

Myocardin (Mycd), which is essential for the differentiation of the smooth muscle cell lineage, is constitutively located in the nucleus, although its family members, myocardin-related transcription factors A and B (MRTF-A/B), mostly reside in the cytoplasm and translocate to the nucleus in response to Rho signaling. The mechanism for their nuclear import is unclear. Here we investigated the me...

K.G. Lieu and E.-H. Shim contributed equally to this paper. Correspondence to David A. Jans: [email protected] E.-H. Shim’s present address is Dept. of Urology, University of Alabama, Birmingham, AL 35233. Abbreviations used in this paper: CLSM, confocal laser scanning microscopy; FL, full length; IBB, importin- binding; IBBL, importin-–binding–like; IMP, importin; IP, immunoprecipitation...

Nuclear import of proteins containing a nuclear localization signal (NLS) is dependent on the presence of a cytoplasmic NLS receptor, the GTPase Ran, and p10/ NTF2. The NLS receptor is a heterodimeric proteins consisting of subunits of approximately 60 and 97 kDa, which have been termed importin alpha/beta, karyopherin alpha/beta, or PTAC 58/ 97. Members of the 60-kDa/importin alpha subunit fam...

Nuclear import of karyophilic proteins is carried out by a variety of mechanisms. We previously showed that two basic helix-loop-helix proteins, NeuroD1 and E47, synergistically affect each other's nuclear import. In this study, we dissected the molecular pathways underlying nuclear import of the NeuroD1/E47 heterodimer. In vitro nuclear import assays indicated that importin α family members ar...

Spodoptera frugiperda (Sf9) importin-alpha-16 is a translocon-associated protein that participates in the early sorting pathway of baculovirus integral membrane proteins destined for the inner nuclear membrane (INM). To discern whether sorting intermediate protein complexes like those observed in insect cells are also formed with mammalian INM proteins, cross-linked complexes of importin-alpha-...

The sterol regulatory element–binding protein-2 (SREBP-2) is produced as a large precursor molecule attached to the endoplasmic reticulum membrane. In response to the sterol depletion, the N-terminal segment of the precursor, which contains a basic helixloop-helix–leucine zipper domain, is released by two sequential cleavages and is translocated to the nucleus, where it activates the transcript...