HSP90AB1: Helping the good and the bad

Abstract

HSP90AB1 (heat shock protein 90 kDA alpha, class B, member 1), also known as HSP90beta, is a member of the large family of HSPs which function as molecular chaperones. Chaperones, by binding to client proteins, support proper protein folding and maintain protein stability, especially after exposure to various kinds of cellular stress. Client proteins belong to various protein families including kinases, ubiquitin ligases and transcription factors. HSP90 proteins act as dimers and bind clients with the help of co-chaperones. The cochaperones influence many functions including client binding, ATPase activity or ATP binding of HSP90. HSPs are necessary for a large scale of cellular processes and therefore essential for cell survival. Since client proteins can be mutant proteins that would be degraded without the help of chaperones, HSPs also promote tumor formation and cancer cell proliferation. As such, they are also targets for new therapeutic approaches in cancer treatment. This review focuses on recent studies on HSP90AB1, if possible in comparison with its close homologue HSP90AA1.

SARS-CoV-2 codon usage bias downregulates host expressed genes with similar codon usage

“…Moreover, this gene, along with S100A11, HSP90AB1 and also EEF1A1, regulates the exocytosis of granules containing inflammatory mediators in neutrophils (24).In addition, our analysis shows a translation decrease in A2M, a plasmatic protein that inhibits a broad spectrum of proteases, including trypsin, thrombin and collagenase (6). Finally, we highlight the presence in our analysis of the HSP90AB1, a known chaperone that facilitates the maturation of a wide range of proteins and its attenuation has been related to idiopathic pulmonary fibrosis and cystic fibrosis (16,43).…”

A proteomics method using immunoaffinity fluorogenic derivatization–liquid chromatography/tandem mass spectrometry (FD‐LC‐MS/MS) to identify a set of interacting proteins

“…The peak area values for peaks 4–6 were 4923, 52953 and 5920, respectively, and the abundance ratios of each HSP90‐beta form for peaks 4–6 were 7.7, 83.0 and 9.3%, respectively (Table ). HSP90 is known to undergo post‐translational modifications, such as phosphorylation (Haase & Fitze, ), and the difference in retention times might be ascribed to these modifications, although the modification types need to be confirmed using MS/MS equipment with a higher throughput in a future study. The proposed immunoaffinity‐FD‐LC–MS/MS method would be useful for detecting subtle differences in the existing forms and investigating their abundance ratio in immunoprecipitated samples.…”

Cytoplasmic sequestration of the RhoA effector mDiaphanous1 by Prohibitin2 promotes muscle differentiation

“…mDia1 interacts with proteins involved in nuclear import and protein folding in MB, suggesting novel stage-specific roles for mDia1 in MB. It's interaction with proteins regulating nuclear import such as Kpnb1, Hsp90ab1and Hsp90aa1 (Hasse and Fitze, 2016;Stelma and Leaner, 2017;Zhong et al, 2014) suggests that mDia1 might shuttle between the nucleus and cytoplasm, similar to mDia2 (Miki et al, 2009;Shao et al, 2015). Consistent with its scaffolding properties (Wallar and Alberts, 2003), mDia1 associates with chaperones such as Hsp90b1, Hsp90ab1, Hsp90aa1 (Schopf et al, 2017), suggesting a potential involvement in regulating protein folding.…”