Predicted structural features of representative metazoan and non-metazoan caveolins. (A) Model summarizing the key structural similarities and difference in different groups of caveolins based on the phylogenetic analysis and structural comparisons presented in Fig. 4 and Data S3. The number of + symbols in each cell represents the frequency of occurrence of a specific structural unit in the caveolins of the corresponding clade. The number in parentheses indicates the average number of amino acids constituting the structural unit within the caveolin clades (rounded to the nearest integer). For Type I-CAV caveolins where the C-terminal β-strand is predicted to be discontinuous in two segments, the average is calculated separately for caveolins with a single C-terminal β-strand and for those with two segments. The results are separated by a comma for the two types of C-terminal β-strands, and the averages for the two segments are separated by a forward slash. (B) Sequence alignment of representative caveolins. Conserved residues are highlighted, with darker intensities corresponding to higher percent identity. Structural features are colored as follows: N-terminal variable region (yellow), pin motif (red), hook region (blue), scaffolding domain (green), spoke region (gray), β-strand (cyan), and C-terminal variable region (purple). (C–N) Different views of AF2.2 models of representative caveolins. (C–E) Human Cav1 (Type II-CAV, Q03135). (F–H)S. purpuratus (Type I-CAV, A0A7M7T4C2). (I–K)A. queenslandica (Atypical-CAV, A0A1X7UHP5). (L–N)S. rosetta (Choa-CAV, F2U793). In C-N, structural features are colored as in panel B. To better display the structure of a single protomer within the complex, the other 10 protomers in the models in panels E, H, K, and N have been made transparent.