Continuity between cytoplasmic endomembranes and outer mitochondrial membranes in fungi

Summary Several types of intimate association are shown between endoplasmic reticulum or endoplasmic reticulum-like membranes and the outer membranes of mitochondria in fungal hyphae. These include close physical association, contact, thread-like continuity, and direct luminal continuity. Membranes are smooth surfaced in the immediate region of association or continuity, and some have ribosomes at other sites along their surfaces. The continuities represent sites of membrane interaction which may facilitate exchange between adjacent membrane components. Additional continuities are shown between mitochondria and other endomembrane components. Observations are discussed in relation to the body of information linking mitochondria and endoplasmic reticulum in a variety of eukaryotic cells.