Crystal structure of the A49M mutant CAP-Gly domain of human Dynactin-1 (p150-Glued) in complex with human EB1 C-terminal hexapeptide
[DCTN1_HUMAN] Defects in DCTN1 are the cause of distal hereditary motor neuronopathy type 7B (HMN7B) [MIM:607641]; also known as progressive lower motor neuron disease (PLMND). HMN7B is a neuromuscular disorder. Distal hereditary motor neuronopathies constitute a heterogeneous group of neuromuscular disorders caused by selective degeneration of motor neurons in the anterior horn of the spinal cord, without sensory deficit in the posterior horn. The overall clinical picture consists of a classical distal muscular atrophy syndrome in the legs without clinical sensory loss. The disease starts with weakness and wasting of distal muscles of the anterior tibial and peroneal compartments of the legs. Later on, weakness and atrophy may expand to the proximal muscles of the lower limbs and/or to the distal upper limbs.    Defects in DCTN1 are a cause of susceptibility to amyotrophic lateral sclerosis (ALS) [MIM:105400]. ALS is a neurodegenerative disorder affecting upper and lower motor neurons, and resulting in fatal paralysis. Sensory abnormalities are absent. Death usually occurs within 2 to 5 years. The etiology is likely to be multifactorial, involving both genetic and environmental factors.  Defects in DCTN1 are the cause of Perry syndrome (PERRYS) [MIM:168605]; also called parkinsonism with alveolar hypoventilation and mental depression. Perry syndrome is a neuropsychiatric disorder characterized by mental depression not responsive to antidepressant drugs or electroconvulsive therapy, sleep disturbances, exhaustion and marked weight loss. Parkinsonism develops later and respiratory failure occurred terminally.
[DCTN1_HUMAN] Required for the cytoplasmic dynein-driven retrograde movement of vesicles and organelles along microtubules. Dynein-dynactin interaction is a key component of the mechanism of axonal transport of vesicles and organelles. [MARE1_HUMAN] Binds to the plus end of microtubules and regulates the dynamics of the microtubule cytoskeleton. Promotes cytoplasmic microtubule nucleation and elongation. May be involved in spindle function by stabilizing microtubules and anchoring them at centrosomes. May play a role in cell migration.   
Publication Abstract from PubMed
Dynamic microtubule plus-end tracking protein (+TIP) networks are implicated in all functions of microtubules, but the molecular determinants of their interactions are largely unknown. Here, we have explored key binding modes of +TIPs by analyzing the interactions between selected CAP-Gly, EB-like, and carboxy-terminal EEY/F-COO(-) sequence motifs. X-ray crystallography and biophysical binding studies demonstrate that the beta2-beta3 loop of CAP-Gly domains determines EB-like motif binding specificity. They further show how CAP-Gly domains serve as recognition domains for EEY/F-COO(-) motifs, which represent characteristic and functionally important sequence elements in EB, CLIP-170, and alpha-tubulin. Our findings provide a molecular basis for understanding the modular interaction modes between alpha-tubulin, CLIPs, EB proteins, and the dynactin-dynein motor complex and suggest that multiple low-affinity binding sites in different combinations control dynamic +TIP networks at microtubule ends. They further offer insights into the structural consequences of genetic CAP-Gly domain defects found in severe human disorders.
Key interaction modes of dynamic +TIP networks.,Honnappa S, Okhrimenko O, Jaussi R, Jawhari H, Jelesarov I, Winkler FK, Steinmetz MO Mol Cell. 2006 Sep 1;23(5):663-71. PMID:16949363
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.