Alternate splicing of dysferlin C2A confers Ca²⁺-dependent and Ca²⁺-independent binding for membrane repair.
Dysferlin plays a critical role in the Ca²⁺-dependent repair of microlesions that occur in the muscle sarcolemma. Of the seven C2 domains in dysferlin, only C2A is reported to bind both Ca²⁺ and phospholipid, thus acting as a key sensor in membrane repair. Dysferlin C2A exists as two isoforms, the "canonical" C2A and C2A variant 1 (C2Av1). Interestingly, these isoforms have markedly different responses to Ca²⁺ and phospholipid. Structural and thermodynamic analyses are consistent with the canonical C2A domain as a Ca²⁺-dependent, phospholipid-binding domain, whereas C2Av1 would likely be Ca²⁺-independent under physiological conditions. Additionally, both isoforms display remarkably low free energies of stability, indicative of a highly flexible structure. The inverted ligand preference and flexibility for both C2A isoforms suggest the capability for both constitutive and Ca²⁺-regulated effector interactions, an activity that would be essential in its role as a mediator of membrane repair.
Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
Kerry
K
Fuson
Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth 55812 MN, USA.
Anne
A
Rice
Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth 55812 MN, USA.
Ryan
R
Mahling
Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
Adam
A
Snow
Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
Kamakshi
K
Nayak
Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
Prajna
P
Shanbhogue
Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
Austin G
AG
Meyer
Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia.
Gregory M I
GM
Redpath
Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth 55812 MN, USA.
Anne
A
Hinderliter
Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia.
Sandra T
ST
Cooper
Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA. Electronic address: roger.b.sutton@ttuhsc.edu.
R Bryan
RB
Sutton
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D018360:Crystallography, X-Ray; D000073939:Dysferlin; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012038:Regeneration; D012508:Sarcolemma / Q000378:metabolism* / Q000648:ultrastructure; D013816:Thermodynamics
C114839:DYSF protein, human; C497505:Dysf protein, mouse; D000073939:Dysferlin; D008565:Membrane Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D002118:Calcium