PROSITE documentation PDOC00487

Stathmin family signatures and stathmin-like (SLD) domain profile

Stathmin [1] (from the Greek 'stathmos' which means relay), is an ubiquitous intracellular protein, present in a variety of phosphorylated forms and which is involved in the regulation of the microtubule (MT) filament system by destabilizing microtubules. It prevents assembly and promotes disassembly of microtubules.

Stathmin belongs to a family that also includes:

• Stathmin 2 (Protein SCG10); a neuron-specific, membrane-associated protein that accumulates in the growth cones of developing neurons. It is highly similar in its sequence to stathmin, but differs in that it contains an additional N-terminal hydrophobic segment of 32 residues which is probably responsible for its interaction with membranes.
• Stathmin 3 (SCG10-like protein; SCLIP) [2]; a protein specifically expressed in neurons.
• Stathmin 4 (Stathmin-like protein B3); which contains an additional N- terminal hydrophobic domain [3].

These proteins possess a stathmin-like domain (SLD) with various N-terminal extensions. SLD is a highly conserved domain of 149 amino acid residues. Structurally, it consists of an N-terminal domain of about 45 residues followed by a 78 residue α-helical domain consisting of a heptad repeat coiled coil structure and a C-terminal domain of 25 residues (see <PDB:1SA0>) [4]. The SLD binds two tubulins arranged longitudinally, head-to-tail, in protofilament-like complexes.

As signatures for proteins of the stathmin family, we selected a conserved decapeptide which ends with the first three residues of the coiled coil domain and a second pattern that corresponds to part of the central region of the coiled coil. We also developed a profile that covers the entire SLD domain.