The best understood system for the transport of macromolecules between the cytoplasm and the nucleus is the classical nuclear import pathway. In this pathway, a protein containing a classical basic nuclear localization signal (NLS) is imported by a heterodimeric import receptor consisting of the ␤-karyopherin importin ␤, which mediates interactions with the nuclear pore complex, and the adaptor protein importin ␣, which directly binds the classical NLS. Here we review recent studies that have advanced our understanding of this pathway and also take a bioinformatics approach to analyze the likely prevalence of this system in vivo. Finally, we describe how a predicted NLS within a protein of interest can be confirmed experimentally to be functionally important.In eukaryotic cells, the genetic material and transcriptional machinery of the nucleus are separated from the translational machinery and metabolic systems of the cytoplasm by the nuclear envelope. This segregation facilitates the precise regulation of cellular processes such as gene expression (1), signal transduction (2), and cell cycle progression (3) through selective regulation of bidirectional transport between the nucleus and the cytoplasm. However, this physical separation also necessitates the existence of molecular machinery that specifically recognizes cargo in one compartment, translocates it through the nuclear pore, and releases it in the other compartment. Nuclear transport systems of this kind were first proposed when a nuclear targeting signal in the simian virus 40 (SV40) 2 large T antigen was characterized more than 20 years ago (4, 5). Since then, several pathways for nucleocytoplasmic transport have been described, of which the classical nuclear import pathway is the best characterized. The integration of detailed structural information on the components of the pathway, whole genome surveys, and extensive molecular analysis has generated powerful insight into the crucial interactions that underlie this pathway. Here we review recent studies that have defined key aspects of the cargo/import receptor interaction in the classical nuclear import cycle and present results of a bioinformatics-based assessment of the likely prevalence of this system within the model eukaryotic organism, Saccharomyces cerevisiae. Overview of Nucleocytoplasmic TransportTransport of macromolecules into and out of the nucleus occurs through large, proteinaceous structures called nuclear pore complexes (NPCs) (6 -9). Nuclear pore complexes allow passive diffusion of ions and small proteins (Ͻ40 kDa) but restrict passage of larger molecules to those containing an appropriate targeting signal (10, 11). The pores are constructed from a class of proteins called "nucleoporins," a subset of which contains a tandem series of phenylalanine-glycine (FG) repeats that line the central transport channel of the pore (8,(12)(13)(14).The active transport of macromolecular cargo between the cytoplasmic and nuclear compartments is facilitated by specific soluble carrier proteins. Th...

Surgical breast reconstruction after mastectomy requires precise perforator coordinates/dimensions, perforator course, and fat volume in a radiology report. Automatic perforator reporting software was implemented as an OsiriX Digital Imaging and Communications in Medicine (DICOM) viewer plugin. For perforator analysis, the user identifies a reference point (e.g., umbilicus) and marks each perforating artery/vein bundle with multiple region of interest (ROI) points along its course beginning at the muscle-fat interface. Computations using these points and analysis of image data produce content for the report. Post-processing times were compared against conventional/manual methods using de-identified images of 26 patients with surgically confirmed accuracy of perforator locations and caliber. The time from loading source images to completion of report was measured. Significance of differences in mean processing times for this automated approach versus the conventional/manual approach was assessed using a paired t test. The mean conventional reporting time for our radiologists was 76 ± 27 min (median 65 min) compared with 25 ± 6 min (median 25 min) using our OsiriX plugin (p < 0.01). The conventional approach had three reports with transcription errors compared to none with the OsiriX plugin. Otherwise, the reports were similar. In conclusion, automated reporting of perforator magnetic resonance angiography (MRA) studies is faster compared with the standard, manual approach, and transcription errors which are eliminated.