神经退行性病
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Figure 2｜ Expression and localization of endogenous wild-type GEMIN5 protein within humans.
Unlike other members of the SMN complex, GEMIN5 is a primarily cytoplasmic protein with some additional nuclear presence (Figure 2C and D), however the protein has also been observed to be concentrated within specific nuclear and cytoplasmic bodies (Gubitz et al., 2002; Hao et al., 2007; Cauchi et al., 2010). Localization within nuclear gems is observed, however unlike most SMN complex members, colocalization between SMN and GEMIN5 is scarce, implying that GEMIN5 is no longer necessary to SMN complex function when in the nucleus (Battle et al., 2007; Hao et al., 2007). Within the cytoplasm, GEMIN5 can be found in association with the SMN complex during Sm core ring construction. Alternatively, the protein can be found associating with GEMIN3, GEMIN4, or completely independent (Battle et al., 2007; Hao et al., 2007). GEMIN5 ortholog localization has also been observed within Drosophila cytoplasmic U-bodies, most likely due to its role in U-rich snRNP biogenesis as their presence is the defining feature of such bodies (Liu and Gall, 2007; Cauchi et al., 2010). Further, GEMIN5 has also been shown to associate with and potentially influence the formation of P-bodies, an interesting though not entirely unexpected observation given the connection with U-bodies (Fierro-Monti et al., 2006; Xu et al., 2016; Jiang et al., 2018; Martinez-Salas et al., 2020). The protein is also recruited into both RNP- and CAPRIN1-associated cytoplasmic granules as part of stress response, though the significance of this localization is unknown (Battle et al., 2007; Vu et al., 2021; Delle Vedove et al., 2022).
Regarding expression between tissue types, GEMIN5 is a ubiquitously expressed protein with little to no tissue specificity, though some exceptions are present. Based on data from The Human Protein Atlas (Uhlén et al., 2015), GEMIN5 protein is characterized as “low” within the liver, heart muscle, and adipose tissue, with “medium” to “high” expression in all other listed tissue types. Notably, GEMIN5 expression appears to be high in the human cerebral cortex and the cerebellum, especially within Purkinje cells (Uhlén et al., 2015). While further studies may increase our understanding of GEMIN5 expression patterns in various tissue types, expression does seem to occur in every human tissue type, indicating general importance in normal biological function (Figure 2A and B).