Involved in cytoplasm to vacuole transport (Cvt), pexophagy, mitophagy and nucleophagy (PubMed:26442587). Recruits mitochondria for their selective degradation via autophagy (mitophagy) during starvation, through its interaction with ATG32 (By similarity). Works as scaffold proteins that recruit ATG proteins to the pre-autophagosome (PAS), the site of vesicle/autophagosome formation (By similarity). Required for ATG9 anterograde transport from the mitochondria to the PAS (By similarity). Recruits also the ATG19-prAPE1 complex to the PAS (By similarity). Required for the Cvt vesicles completion (By similarity). Homodimer and potential homooligomers (By similarity). Interacts with ATG1 kinase and the ATG19 and ATG34 cargo protein transporters (By similarity). Interacts with ATG9, ATG17 and ATG20 (By similarity). During pexophagy, accumulates in the vacuolar membrane region, where the peroxisomes contact the vacuole (By similarity). Impairs the cytoplasm to vacuole transport (Cvt) pathway (PubMed:26442587). Mislocalizes ATG8 in the cytosol, when ATG17, ATG29 or ATG31 are also deleted (PubMed:26442587). Kluyveromyces marxianus proteins are shorter in length and have a more ordered secondary structure than their S.cerevisiae counterparts, which might contribute to the superior thermotolerance and solubility (PubMed:26442587). K.marxianus could be therefore useful as a new model organism for further elucidation of the molecular details of autophagy (PubMed:26442587). Belongs to the ATG11 family.