Fig. 5. Comparison of adhesion complexes in vertebrates and C. elegans. (A) A vertebrate focal adhesion and C. elegans dense body. Only conserved proteins are shown. Focal adhesions contain numerous adaptor and signaling proteins not shown here (refer to Zamir and Geiger, 2001). A few downstream effectors are indicated by the dashed arrows. (B) A vertebrate hemidesmosome and C. elegans fibrous organelles. (For more on hemidesmosome composition, see Nievers et al., 1999; Roper et al., 2002.) Like hemidesmosomes, fibrous organelles anchor IFs through a plectin-family member (VAB-10A). The transmembrane proteins MUA-3 and MUP-4 are located apically and myotactin is located basally. VAB-19 may be located both basally and apically. The protein-protein interactions shown for fibrous organelles are speculative, since it is currently unclear whether myotactin, MUA-3 or MUP-4 interacts directly with VAB-10A or IFs. (C) The dystrophinglycoprotein complex (DGC) in vertebrates and C. elegans. Other proteins are known to associate with the mammalian DGC (reviewed by Ehmsen et al., 2002), but have not been shown for simplicity. C. elegans does not have any clear sarcospan or nNOS homologs (Segalat, 2002). Currently, it is unclear whether the putative C. elegans DGC is present in epidermal, muscle, and/or neuronal tissues (see text for details).