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Hsp90 is a ubiquitous molecular chaperone involved in many cell signaling pathways, and its interactions with specific chaperones and cochaperones determines which client proteins to fold. Hsp90 has been shown to be involved in the promotion and maintenance of proper protein complex assembly either alone or in association with other chaperones such as the R2TP chaperone complex. Hsp90-R2TP acts through several mechanisms, such as by controlling the transcription of protein complex subunits, stabilizing protein subcomplexes before their incorporation into the entire complex, and by recruiting adaptors that facilitate complex assembly. Despite its many roles in protein complex assembly, detailed mechanisms of how Hsp90-R2TP assembles protein complexes have yet to be determined, with most findings restricted to proteomic analyses and in vitro interactions. This review will discuss our current understanding of the function of Hsp90-R2TP in the assembly, stabilization, and activity of the following seven classes of protein complexes: L7Ae snoRNPs, spliceosome snRNPs, RNA polymerases, PIKKs, MRN, TSC, and axonemal dynein arms. [ABSTRACT FROM AUTHOR]

Diagnosis of primary ciliary dyskinesia (PCD) by identification of dynein arm loss in transmission electron microscopy (TEM) images can be confounded by high background noise due to random electron-dense material within the ciliary matrix, leading to diagnostic uncertainty even for experienced morphologists. The authors developed a novel image analysis tool to average the axonemal peripheral microtubular doublets, thereby increasing microtubular signal and reducing random background noise. In a randomized, double-blinded study that compared two experienced morphologists and three different diagnostic approaches, they found that use of this tool led to improvement in diagnostic TEM test performance. [ABSTRACT FROM AUTHOR]

No abstract available. Article truncated at 150 words. A 52 year old woman was admitted for dyspnea and fatigue. Kartagener syndrome had been diagnosed at age 3 with situs inversus totalis (Figures 1 and 2). She has bronchiectasis (Figure 3) with chronic Pseudomonas colonization, chronic sinusitis, and nasal polyposis. Kartagener syndrome is a type of primary cilia dyskinesia or immotile-cilia syndrome. When primary ciliary dyskinesia is combined with situs inversus it is known as Kartagener syndrome (KS) after the Swiss internist who recognized the association of situs inversus, bronchiectasis and sinusitis (1). It is popular in case presentations especially with the chest x-ray or CT scans deliberated presented inverted. KS is an autosomal recessive disorder of the ciliary axoneme with incomplete penetrance and extensive heterogeneity (2). The typical ciliary axoneme consists of 2 central microtubules surrounded by 9 microtubular doublets. Patients with primary ciliary dyskinesia exhibit a wide range of defects in ciliary ultrastructure and motility, which ultimately …

Kartagener's syndrome (KS) is a clinical variant of primary ciliary dyskinesia involving situs inversus associated with chronic airway infections. We studied two sisters; the elder one had dextrocardia and scoliosis, and the younger one had situs inversus of the lung, liver, and stomach as well as dextrocardia. Both patients had chronic sinusitis and chronic bronchitis with bronchiectasis. In both cases, the ciliary defect associated with this syndrome is the absence of inner dynein arms. [ABSTRACT FROM AUTHOR]

Primary ciliary dyskinesia (PCD) is a phenotypically and genetically heterogeneous disorder with an autosomal‐recessive inheritance pattern. Only rarely other modes of inheritance such as X‐linked transmission are observed. The disease phenotype is caused by defects of respiratory cilia, sperm tails and the cilia of the embryonic node. The lack of mucociliary clearance contributes to recurrent respiratory tract infections, that might progress to permanent lung damage (bronchiectasis). The goal of therapy is prevention of bronchiectasis. Male infertility due to sperm tail dysmotility is another frequent finding in PCD. Half of affected individuals have situs inversus (Kartagener's syndrome) due to randomization of left/right body asymmetry. Currently three genes ( DNAI1 , DNAH5 , DNAH11 ) that encode for dynein proteins have been linked to recessive PCD. Mutations in RPGR located on the X chromosome have been identified in males with retinitis pigmentosa and PCD. As a screening test nasal nitric oxide (NO) measurement is widely used. Establishment of diagnosis currently relies on electron microscopy, direct evaluation of ciliary beat by light microscopy, and/or the novel method of high‐resolution immunofluorecent analysis of respiratory cilia. [ABSTRACT FROM AUTHOR]

Kartagener's syndrome has been characterized by a primary ultrastructural abnormality of the cilia which consequently impairs their movements. We used transmission electron microscopy with tannic acid staining to investigate the fine structure of the cilia from the nasal mucosa of a 7-year-old girl with Kartagener's syndrome. The staining technique employed was useful for visualizing the dynein arms and protofilaments of the microtubules of the cilia. Although 15% of the cilia examined demonstrated microtubular disarrangements, these findings were considered to be acquired changes due to chronic sinusitis. No abnormal ciliary ultrastructures specific to Kartagener's syndrome, such as absence of dynein arms, were detected in this study. In such cases without any abnormal ciliary ultrastructures, it is conceivable that some other unknown factor may be involved in the impaired ciliary movement. [ABSTRACT FROM AUTHOR]

Abstract Diagnosis of primary ciliary dyskinesia (PCD) by identification of dynein arm loss in transmission electron microscopy (TEM) images can be confounded by high background noise due to random electron-dense material within the ciliary matrix, leading to diagnostic uncertainty even for experienced morphologists. The authors developed a novel image analysis tool to average the axonemal peripheral microtubular doublets, thereby increasing microtubular signal and reducing random background noise. In a randomized, double-blinded study that compared two experienced morphologists and three different diagnostic approaches, they found that use of this tool led to improvement in diagnostic TEM test performance.