Autophagy is a constitutive, dynamic, bulk degradation process that is necessary for a number of processes in eukaryotic cells. During autophagy, long-lived proteins and organelles are engulfed by specialized double membrane vesicles (autophagosomes) and delivered to the lysosomes for degradation. Although constitutive, autophagy can be enhanced above basal levels by various stimuli, such as amino acid starvation.
We recently showed that SFV infection induces the accumulation of autophagosomes in infected cells (Eng et al., 2012). We showed that although autophagosomes accumulated, the viral proteins were largely absent from the vesicles and were not degraded in lysosomes. Further, although the rate of formation of autophagosomes was increased in infected cells, we showed that the autophagosome accumulation was largely due to a block in their degradation in lysosomes rather than a strong induction in their formation. Expression of the SFV glycoprotein complex was found to be necessary for the block of autophagosome degradation.
In 2010, we developed and published a flow-cytometry based assay for autophagic flux (Eng et al., 2010). For more details, see under Protocols.
Publications on this topic
Thaa, B., Biasiotto, R., Eng, K., Neuvonen, M., Götte, B., Rheinemann, L., Balistreri, G., Merits, A., Ahola, T. and McInerney, G.M. (2015) Differential PI3K–Akt–mTOR activation by Semliki Forest and chikungunya virus, dependent on nsP3 and connected to replication complex internalisation. J Virol, 89:11420-37.
Klionsky, D. et al., approx 1200 authors listed alphabetically, including Eng, K, and McInerney, G.M. (2012). Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes. Autophagy, 8:445-544.
Eng, K.E., Panas, M.D., Murphy, D., Karlsson Hedestam, G.B. and McInerney, G.M. (2012). Accumulation of autophagosomes in Semliki Forest virus infected cells is dependent on the expression of viral structural proteins. J Virol 86:5674-5685.
Eng, K.E., Panas, M., Karlsson Hedestam, G.B., and McInerney, G.M. (2010). A novel flow cytometry based assay for autophagic flux. Autophagy 6:634-641.