Biomedical subjects
J Franke
Publications and source records attributed to J Franke.
Scrutinizing screening. Are we doing all we can for our newborns?
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Initial characterization of the nascent polypeptide-associated complex in yeast.
The three subunits of the nascent polypeptide-associated complex (alpha, beta1, beta3) in Saccharomyces cerevisiae are encoded by three genes (EGD2, EGD1, BTT1). We found the complex bound to ribosomes via the beta-subunits in a salt-sensitive manner, in close proximity to nascent polypeptides. Estimation of the molecular weight of the complex of wild-type cells and cells lacking one or two subunits revealed that the composition of the complex is variable and that as yet unknown proteins might be included. Regardless of the variability, a certain balance of the subunits has to be maintained: the deletion of one subunit causes downregulation of the remaining subunits at physiological growth temperature. Cells lacking both beta-subunits are unable to grow at 37 degrees C, most likely due to a toxic effect of the alpha-subunit. Based on in vitro experiments, it has been proposed that the function of mammalian nascent-polypeptide associated complexes (NAC) is to prevent inappropriate targeting of non-secretory nascent polypeptides. In vivo, however, the lack of NAC does not cause secretion of signal-less invertase in yeast. This result and the lack of a drastic phenotype of cells missing one, two or three subunits at optimal conditions (28 degrees C, YPD-medium) suggest either the existence of a substitute for NAC or that cells tolerate or 'repair' the damage caused by the absence of NAC.
[Ultrasonography as a diagnostic tool in cases of quadriceps tendon rupture].
AIM: Determination of the reliability of ultrasonography as a diagnostic tool for rupture of the quadriceps tendon and for follow-up after surgical repair. METHOD: 11 patients (12 tendons) with a clinical suspicion of quadriceps tendon rupture were studied with ultrasonography in two planes. RESULTS: In 9 cases we were able to confirm the results of the clinical examination using ultrasonography. In 2 cases we did not find a rupture of the quadriceps tendons ultrasonographically. Within the postoperative follow-up, the homogeneity and echogeneity normalised after the sixth week. CONCLUSION: Using ultrasonography we are able to clearly diagnose ruptures of the quadriceps tendon and objectively assess the postoperative follow-up.
[Diagnostic ultrasonography of the sternoclavicular joint].
PURPOSE: To evaluate the value of ultrasonography in the diagnosis of swelling and lesions of the sternoclavicular joint (SCG). MATERIAL AND METHODS: We analysed the sonograms of 20 SCG of 18 patients with pain and swelling of the SCG. Ultrasonography was performed just after the clinical examination, using a 7.5 MHz linear scanner. RESULTS: All examinations of the SCG produced distinct and clear sonographical findings. We showed that luxations of the SCG as well as tumors and local inflammation can be identified. CONCLUSION: Ultrasonographic examination is a noninvasive, time sparing and economical diagnostic tool for clarifying the differential diagnosis of lesions of the SCG and establish may a therapy regimen.
RanBP3 contains an unusual nuclear localization signal that is imported preferentially by importin-alpha3.
The full range of sequences that constitute nuclear localization signals (NLSs) remains to be established. Even though the sequence of the classical NLS contains polybasic residues that are recognized by importin-alpha, this import receptor can also bind cargo that contains no recognizable signal, such as STAT1. The situation is further complicated by the existence of six mammalian importin-alpha family members. We report the identification of an unusual type of NLS in human Ran binding protein 3 (RanBP3) that binds preferentially to importin-alpha3. RanBP3 contains a variant Ran binding domain most similar to that found in the yeast protein Yrb2p. Anti-RanBP3 immunofluorescence is predominantly nuclear. Microinjection of glutathione S-transferase-green fluorescent protein-RanBP3 fusions demonstrated that a region at the N terminus is essential and sufficient for nuclear localization. Deletion analysis further mapped the signal sequence to residues 40 to 57. This signal resembles the NLSs of c-Myc and Pho4p. However, several residues essential for import via the c-Myc NLS are unnecessary in the RanBP3 NLS. RanBP3 NLS-mediated import was blocked by competitive inhibitors of importin-alpha or importin-beta or by the absence of importin-alpha. Binding assays using recombinant importin-alpha1, -alpha3, -alpha4, -alpha5, and -alpha7 revealed a preferential interaction of the RanBP3 NLS with importin-alpha3 and -alpha4, in contrast to the simian virus 40 T-antigen NLS, which interacted to similar extents with all of the isoforms. Nuclear import of the RanBP3 NLS was most efficient in the presence of importin-alpha3. These results demonstrate that members of the importin-alpha family possess distinct preferences for certain NLS sequences and that the NLS consensus sequence is broader than was hitherto suspected.
Naming names. TDH implements HIV/STD reporting changes.
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