CMM 577 EXAM 2 2024 WITH 100% CORRECT ANSWERS

What are the three different cytoskeletal elements? Describe them. - correct answer Actin: Responsible for cell protrusions Concentrated at the cell cortex Organize into bundles/networks Microtubules: Long, larger, Made of tubulin Give rise to cilia, mitotic spindles and interphase array Intermediate Filaments: Ropelike fibers made of IF proteins Mechanical strength and support for the entire cell and nuclear lamina Describe the classification system of IF's? - correct answer 5 Main Types: Toward the N terminus there is a head domain, form a dimer through coiled coil interaction. C terminal has C terminal tails. Tripartite structure: alpha helical central rod flacked by non helical head and tail domains of variable length and sequence. Thought to regulate intxns b/w Ifs and other proteins. Head domains are essential for IF assembly. Tail domains involved in lateral IF intxns and organization of IF networks. Describe the conserved structural motifs of IF protein subunits. - correct answer Coiled coil is a structural motif where 2-7 alpha helices are coiled together like strands of a rope (typically dimers and trimers). Tertiary structure-protein protein interaction motif, happens in regions that are encoded by alpha helices and that are elongated structures. Coiled coils are composed of heptad repeats, repeating pattern of 7 AAS stabilized by hydrophobic intxns b/w residues in the a and d positions. G position is charge