Caldesmon

Caldesmon 1, also known as CALD1, is a human gene. Caldesmon is a calmodulin-binding protein. Like Calponin, Caldesmon tonically inhibits the ATPase activity of myosin in smooth muscle. This gene encodes a Calmodulin and actin-binding protein that play an essential role in the regulation of smooth muscle and nonmuscle contraction.

Two closely-related variants of human Caldesmon have been identified. The h-Caldesmon variant (120–150 kD) is predominantly expressed in smooth muscle, whereas I-Caldesmon (70–80 kD) is found in non-muscle tissue and cells. Neither of the two variants has been detected in skeletal muscle. Anti-Caldesmon recognizes only the h-Caldesmon variant. Anti-Caldesmon antibody labels smooth muscle and tumors of smooth muscle, myofibroblastic, and myoepithelial differentiation. Anti-Caldesmon has also been used to differentiate Epithelioid Mesothelioma from Serous Papillary Carcinoma of the ovary.

Anti-Caldesmon (CALD-31) is a mouse monoclonal antibody derived from cell culture supernatant that is concentrated, dialyzed, filter sterilized and diluted in buffer pH 7.5, containing BSA and sodium azide as a preservative.

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1. Cut and mount 3-4 micron formalin-fixed paraffin-embedded tissues on positive charged slides.
2. Air dry for 2 hours at 58° C.
3. Deparaffinize, dehydrate and rehydrate tissues.
4. Subject tissues to heat epitope retrieval using a suitable retrieval solution such as ImmunoDNA Retriever with Citrate (BSB 0020-BSB 0023) or EDTA (BSB 0030-BSB 0033).
5. Any of three heating methods may be used:
   • Electric Pressure Cooker
     Place standoff rack at base of pressure cooker. Add 1-2 inches of distilled water to the pressure cooker and turn heat to high, and incubate for 15 minutes. Open and immediately transfer slides to room temperature.
   • Water Bath Method
     Place tissues/slides in a pre-warmed staining dish or coplin jar containing the ImmunoDNA Retriever with Citrate or EDTA in a water bath set at 95°-99° C. Incubate for 30-60 minutes.
   • Conventional Steamer Method
     Place tissues/slides in a pre-warmed staining dish or coplin jar containing the ImmunoDNA Retriever with Citrate or EDTA in a Steamer, cover and steam for 30-60 minutes.
6. After heat treatment, transfer slides in ImmunoDNA Retriever with Citrate or EDTA to room temperature and let stand for 15-20 minutes.
7. Wash slides with IHC wash buffer or DI water.
8. Continue IHC staining protocol.