REEP5 depletion causes sarco-endoplasmic reticulum vacuolization and cardiac functional defects

Abstract

The sarco-endoplasmic reticulum (SR/ER) plays an important role in the development and progression of many heart diseases. However, many aspects of its structural organization remain largely unknown, particularly in cells with a highly differentiated SR/ER network. Here, we report a cardiac enriched, SR/ER membrane protein, REEP5 that is centrally involved in regulating SR/ER organization and cellular stress responses in cardiac myocytes. In vitro REEP5 depletion in mouse cardiac myocytes results in SR/ER membrane destabilization and luminal vacuolization along with decreased myocyte contractility and disrupted Ca 2+ cycling. Further, in vivo CRISPR/Cas9-mediated REEP5 loss-of-function zebrafish mutants show sensitized cardiac dysfunction upon short-term verapamil treatment. Additionally, in vivo adeno-associated viral (AAV9)-induced REEP5 depletion in the mouse demonstrates cardiac dysfunction. These results demonstrate the critical role of REEP5 in SR/ER organization and function as well as normal heart function and development.

Functional culture and in vitro genetic and small-molecule manipulation of adult mouse cardiomyocytes

“…In parallel experiments, we also demonstrated knockdown of gene expression in these cells, further emphasising the utility of the cellular isolation methodology. Specifically, as the SR adaptor protein Reep5 is known to be essential in maintaining cardiac function 23 , AAV9-mediated Reep5 shRNA knockdown ( Fig. 4d) was performed and cells were analyzed at d3 or d4.…”

Combined transcriptome and proteome analyses reveal differences in the longissimus dorsi muscle between Kazakh cattle and Xinjiang brown cattle

“…(receptor paraprotein 5) leads to defects in cardiac function and vacuolation of the endoplasmic reticulum [39]. A missense mutation (p. G274R) in the ASPA (aspartate acylase) gene caused Canavan disease in a Pakistani family [40].…”

Bioinformatic analysis of membrane and associated proteins in murine cardiomyocytes and human myocardium

“…1a ). Our earlier studies focused on two of these proteins, TMEM65 and REEP5, in detailed biochemical analyses, identifying their specific roles in regulating cardiac conduction and cardiac muscle sarcoplasmic reticulum organization and function, respectively 10 , 12 . Here, we performed a detailed analysis of all 550 identified cardiac membrane proteins and showed that GO term-associated classifications demonstrated 50% of the identified protein clusters had a predicted transmembrane domain and 60% of them contained the GO term “membrane” (Fig.…”