1m46
From Proteopedia
CRYSTAL STRUCTURE OF MLC1P BOUND TO IQ4 OF MYO2P, A CLASS V MYOSIN
Structural highlights
Function[MLC1_YEAST] Essential light chain for the class II conventional myosin MYO1. Acts also as light chain for the class V unconventional myosin MYO2 and for IQG1. Involved in the assembly of the contractile actomyosin ring at the bud neck during cytokinesis by recruiting IQG1 to the bud neck. Also required for chitin and MYO2-dependent secretory vesicle deposition to the center of the bud neck for septum formation. May stabilize MYO2 by binding to its IQ domains. Its major function is probably not to regulate MYO1 activity, but rather to coordinate actin ring formation and targeted membrane deposition during cytokinesis via its interactions with MYO1, IQG1 and MYO2.[1] [2] [3] [MYO2_YEAST] Myosin heavy chain that is required for the cell cycle-regulated transport of various organelles and proteins for their segregation. Functions by binding with its tail domain to receptor proteins on organelles and exerting force with its N-terminal motor domain against actin filaments, thereby transporting its cargo along polarized actin cables. Essential for the delivery of secretory vesicles to sites of active growth during bud emergence and cytokinesis. Required for segregation and inheritance of peroxisomes, late Golgi compartments, mitochondria and the vacuole to the daughter cell during cell division. Also required for correct alignment of the spindle during mitosis.[4] [5] [6] [7] [8] [9] [10] [11] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIQ motifs are widespread in nature. Mlc1p is a calmodulin-like myosin light chain that binds to IQ motifs of a class V myosin, Myo2p, and an IQGAP-related protein, Iqg1p, playing a role in polarized growth and cytokinesis in Saccharomyces cerevisiae. The crystal structures of Mlc1p bound to IQ2 and IQ4 of Myo2p differ dramatically. When bound to IQ2, Mlc1p adopts a compact conformation in which both the N- and C-lobes interact with the IQ motif. However, in the complex with IQ4, the N-lobe no longer interacts with the IQ motif, resulting in an extended conformation of Mlc1p. The two light chain structures relate to two distinct subfamilies of IQ motifs, one of which does not interact with the N-lobes of calmodulin-like light chains. The correlation between light chain structure and IQ sequence is demonstrated further by sedimentation velocity analysis of complexes of Mlc1p with IQ motifs from Myo2p and Iqg1p. The resulting 'free' N-lobes of myosin light chains in the extended conformation could mediate the formation of ternary complexes during protein localization and/or partner recruitment. Two distinct myosin light chain structures are induced by specific variations within the bound IQ motifs-functional implications.,Terrak M, Wu G, Stafford WF, Lu RC, Dominguez R EMBO J. 2003 Feb 3;22(3):362-71. PMID:12554638[12] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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