HSP27 Recombinant Protein

The protein encoded by this gene is induced by environmental stress and developmental changes. The encoded protein is involved in stress resistance and actin organization and translocates from the cytoplasm to the nucleus upon stress induction. Defects in this gene are a cause of Charcot-Marie-Tooth disease type 2F (CMT2F) and distal hereditary motor neuropathy (dHMN). [provided by RefSeq, Oct 2008]

Function: Involved in stress resistance and actin organization.

Subunit structure: Interacts with TGFB1I1

By similarity. Associates with alpha- and beta-tubulin, microtubules and CRYAB. Interacts with HSPB8 and HSPBAP1. Ref.3 Ref.24

Subcellular location: Cytoplasm. Nucleus. Cytoplasm › cytoskeleton › spindle. Note: Cytoplasmic in interphase cells. Colocalizes with mitotic spindles in mitotic cells. Translocates to the nucleus during heat shock and resides in sub-nuclear structures known as SC35 speckles or nuclear splicing speckles. Ref.3 Ref.33

Tissue specificity: Detected in all tissues tested: skeletal muscle, heart, aorta, large intestine, small intestine, stomach, esophagus, bladder, adrenal gland, thyroid, pancreas, testis, adipose tissue, kidney, liver, spleen, cerebral cortex, blood serum and cerebrospinal fluid. Highest levels are found in the heart and in tissues composed of striated and smooth muscle. Ref.16

Induction: Expressed in response to environmental stresses such as heat shock, or estrogen stimulation in MCF-7 cells. Up-regulated in response to enterovirus 71 (EV71) infection (at protein level). Ref.27

Post-translational modification: Phosphorylated in MCF-7 cells on exposure to protein kinase C activators and heat shock. Ref.14 Ref.15 Ref.17 Ref.20 Ref.21 Ref.22 Ref.23 Ref.25 Ref.34Phosphorylation by MAPKAPK2 and MAPKAPK3 in response to stress leads to dissociate HSP27/HSPB1 from large small heat-shock protein (sHsps) oligomers and impair its chaperone activity and ability to protect against oxidative stress effectively. Phosphorylation by MAPKAPK5 in response to PKA stimulation induces F-actin rearrangement.

Involvement in disease: Charcot-Marie-Tooth disease 2F (CMT2F) [MIM:606595]: A dominant axonal form of Charcot-Marie-Tooth disease, a disorder of the peripheral nervous system, characterized by progressive weakness and atrophy, initially of the peroneal muscles and later of the distal muscles of the arms. Charcot-Marie-Tooth disease is classified in two main groups on the basis of electrophysiologic properties and histopathology: primary peripheral demyelinating neuropathies (designated CMT1 when they are dominantly inherited) and primary peripheral axonal neuropathies (CMT2). Neuropathies of the CMT2 group are characterized by signs of axonal regeneration in the absence of obvious myelin alterations, normal or slightly reduced nerve conduction velocities, and progressive distal muscle weakness and atrophy. Nerve conduction velocities are normal or slightly reduced. Onset of Charcot-Marie-Tooth disease type 2F is between 15 and 25 years with muscle weakness and atrophy usually beginning in feet and legs (peroneal distribution). Upper limb involvement occurs later.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.40 Ref.41Neuronopathy, distal hereditary motor, 2B (HMN2B) [MIM:608634]: 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.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.40

Sequence similarities: Belongs to the small heat shock protein (HSP20) family.

Sequence caution: The sequence AAA62175.1 differs from that shown. Reason: Frameshift at position 194. The sequence AAB20722.1 differs from that shown. Reason: Frameshift at position 194. The sequence CAA34498.1 differs from that shown. Reason: Frameshift at position 194.