(A) Domain architecture diagrams for IC from Drosophila melanogaster (Dros. IC) and Rattus norvegicus (Rat IC2C) and constructs used in earlier work are provided for comparison. Proteins and constructs used in this work are from Chaetomium thermophilum (Ct). All ICs have an N-terminal single α-helix (SAH), followed by either a transient/nascent or folded second helix (H2). In Ct, there is an additional helix (H3). The Tctex (orange), LC8 (red), and LC7 (yellow) binding sites are well characterized in Dros. IC and Rat IC2C, and their position in Ct were predicted based on sequence and structure comparison. The C-terminal domain is predicted to contain seven WD40 repeats. The Ct constructs ICFL, IC1-88, IC37-88, IC1-260, IC100-260, IC140-260, IC216-260, and IC216-260 are used in this paper; the IC1-35 construct was used in prior work. Ct p150Glued is predicted to have a Cap-Gly domain near the N-terminus, and two coiled-coil (CC) domains, CC1 and CC2, that are separated by an intercoil domain. CC1 is further divided into two regions called CC1A and CC1B. p150478-680 (p150CC1B) is the construct used in this work. Ct NudE is predicted to have an N-terminal CC region followed by disorder. NudE1-190 (NudECC) is the construct used in this work. (B) Contextual models of dynein with the heavy chains (HC) crudely shown in dark gray. IC in the subcomplex (light gray) is shown in the same orientation as the domain architecture schematic in panel A. The top model depicts the interaction between the p150Glued subunit of dynactin (blue) and the SAH and H2 regions of IC while the bottom model depicts the interaction between NudECC (green) and the SAH region of IC. In both models, dynein is a processive motor traveling toward the minus end of a microtubule, and IC is shown with the homodimeric dynein light chains: Tctex (orange), LC8 (red), and LC7 (yellow).